m (money, center cube)
1.  Rollout^{1}  Bar/23* 13/8  eq: +0.209 
 Player: Opponent:  56.41% (G:16.34% B:0.96%) 43.59% (G:23.28% B:3.22%)  Conf.: ± 0.009 (+0.200...+0.218)  [100.0%] Duration: 1 hour 34 minutes 

2.  Rollout^{1}  Bar/23* 14/9  eq: +0.005 (0.203) 
 Player: Opponent:  53.12% (G:14.92% B:0.83%) 46.88% (G:24.48% B:1.70%)  Conf.: ± 0.009 (0.004...+0.015)  [0.0%] Duration: 1 hour 41 minutes 

3.  Rollout^{1}  Bar/23* 12/7  eq: 0.069 (0.278) 
 Player: Opponent:  50.64% (G:15.08% B:0.90%) 49.36% (G:25.98% B:2.38%)  Conf.: ± 0.009 (0.078...0.060)  [0.0%] Duration: 1 hour 34 minutes 

4.  Rollout^{1}  Bar/23* 7/2*  eq: 0.144 (0.353) 
 Player: Opponent:  47.13% (G:17.20% B:1.40%) 52.87% (G:28.73% B:4.31%)  Conf.: ± 0.009 (0.153...0.135)  [0.0%] Duration: 1 hour 40 minutes 


^{1} 5184 Games rolled with Variance Reduction. Dice Seed: 75310303 Moves: 3ply, cube decisions: XG Roller

Sorry for the delay in posting answers. Recently, life's been busy.
As Tim and Stick opined (a few months ago), the answers to my problems have often been deducible by QF. To be a bit less predictable, I posted a problem where the correct play is best at all scores... and this ploy "worked" to some extent. Be that (sidelight) as it may, this position demonstrates that in primevsprime positions, frequently the key idea is to "put the checkers where they want to go."
Below are some of the more insightful comments (in order of response):
Joe Russell: Bar23, 138 looks right in all scenarios, other than possibly GS. Other, more passive plays, just seem weak, as white will hit on its 2point with entering 6's anyway ...Bar23, 138 threatens to make a serious counter prime and, also, leaves a plethora of numbers to complete the prime if missed or hit back if white hits a fly shot on the 8point.
Ian Dunstan: The move I want to make foremost is b/23* 13/8. Attempting to make a 5th consecutive part of the prime looks paramount to me. This is the move I want to make before thinking about cube position and score.
Igor: First, my DMP move is bar/23* 13/8 ...attempt to counterprime white since we now both have two checkers back. I don't see any factors that would make me change this move for money, regardless of the position of the cube.
Robert Chow: My play is 13/8 in all situations except at gammon save where I would play 14/9. Even at gammon save, 13/8 might be right because the need to make the 8 point may outweigh the danger of having five blots scooped up in the worst case scenario.
If White fans after Blue plays "8" (8pt, bar/23* 13/8), Blue can offer a powerful redouble (by rollout, 8FR is .93). If White fans after any other play, Blue will not even have a double (9FC, which is closest, is only .57).
Above is the rollout for money, center cube. Below are rollouts with the other cube positions and scores. Following that is a nacbracs summary, and a cusp variant (with more rollouts).
+C (money, owning cube)
1.  Rollout^{1}  Bar/23* 13/8  eq: +0.273 
 Player: Opponent:  56.20% (G:16.58% B:1.02%) 43.80% (G:23.66% B:3.54%)  Conf.: ± 0.009 (+0.265...+0.282)  [100.0%] Duration: 1 hour 29 minutes 

2.  Rollout^{1}  Bar/23* 14/9  eq: +0.187 (0.086) 
 Player: Opponent:  53.21% (G:15.28% B:0.83%) 46.79% (G:24.21% B:1.58%)  Conf.: ± 0.006 (+0.181...+0.194)  [0.0%] Duration: 1 hour 29 minutes 

3.  Rollout^{1}  Bar/23* 12/7  eq: +0.099 (0.175) 
 Player: Opponent:  50.62% (G:15.34% B:0.94%) 49.38% (G:26.08% B:2.50%)  Conf.: ± 0.006 (+0.093...+0.105)  [0.0%] Duration: 1 hour 20 minutes 

4.  Rollout^{1}  Bar/23* 7/2*  eq: 0.011 (0.284) 
 Player: Opponent:  47.01% (G:17.32% B:1.39%) 52.99% (G:28.62% B:4.43%)  Conf.: ± 0.007 (0.018...0.004)  [0.0%] Duration: 1 hour 32 minutes 


^{1} 5184 Games rolled with Variance Reduction. Dice Seed: 85576101 Moves: 3ply, cube decisions: XG Roller

–C (money with Opp owning cube)
1.  Rollout^{1}  Bar/23* 13/8  eq: 0.091 
 Player: Opponent:  56.25% (G:16.64% B:1.02%) 43.75% (G:23.67% B:3.47%)  Conf.: ± 0.006 (0.097...0.085)  [100.0%] Duration: 1 hour 31 minutes 

2.  Rollout^{1}  Bar/23* 14/9  eq: 0.179 (0.088) 
 Player: Opponent:  53.40% (G:15.33% B:0.89%) 46.60% (G:24.14% B:1.62%)  Conf.: ± 0.007 (0.186...0.172)  [0.0%] Duration: 1 hour 27 minutes 

3.  Rollout^{1}  Bar/23* 12/7  eq: 0.258 (0.167) 
 Player: Opponent:  50.96% (G:15.20% B:0.94%) 49.04% (G:25.76% B:2.41%)  Conf.: ± 0.006 (0.264...0.252)  [0.0%] Duration: 1 hour 15 minutes 

4.  Rollout^{1}  Bar/23* 7/2*  eq: 0.358 (0.267) 
 Player: Opponent:  47.14% (G:17.34% B:1.46%) 52.86% (G:28.55% B:4.36%)  Conf.: ± 0.007 (0.365...0.351)  [0.0%] Duration: 1 hour 35 minutes 


^{1} 5184 Games rolled with Variance Reduction. Dice Seed: 85576101 Moves: 3ply, cube decisions: XG Roller

d (double match point)
1.  Rollout^{1}  Bar/23* 13/8  eq: +0.135 
 Player: Opponent:  56.76% (G:15.07% B:1.99%) 43.24% (G:26.13% B:5.96%)  Conf.: ± 0.003 (+0.132...+0.139)  [100.0%] Duration: 1 hour 00 minute 

2.  Rollout^{1}  Bar/23* 14/9  eq: +0.082 (0.053) 
 Player: Opponent:  54.09% (G:14.31% B:2.00%) 45.91% (G:26.59% B:4.79%)  Conf.: ± 0.003 (+0.078...+0.085)  [0.0%] Duration: 56 minutes 18 seconds 


^{1} 5184 Games rolled with Variance Reduction. Dice Seed: 49207271 Moves: 3ply, cube decisions: XG Roller

s (gammon save)
1.  Rollout^{1}  Bar/23* 13/8  eq: 0.341 
 Player: Opponent:  55.98% (G:15.58% B:2.33%) 44.02% (G:23.04% B:5.29%)  Conf.: ± 0.005 (0.346...0.336)  [100.0%] Duration: 1 hour 21 minutes 

2.  Rollout^{1}  Bar/23* 14/9  eq: 0.402 (0.061) 
 Player: Opponent:  52.99% (G:14.51% B:2.18%) 47.01% (G:23.10% B:3.34%)  Conf.: ± 0.005 (0.407...0.397)  [0.0%] Duration: 1 hour 13 minutes 


^{1} 5184 Games rolled with Variance Reduction. Dice Seed: 49207271 Moves: 3ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10, MET: Kazaross XG2
g (gammon go)
1.  Rollout^{1}  Bar/23* 13/8  eq: +0.461 
 Player: Opponent:  55.79% (G:17.26% B:2.21%) 44.21% (G:26.38% B:6.13%)  Conf.: ± 0.005 (+0.456...+0.466)  [100.0%] Duration: 1 hour 16 minutes 

2.  Rollout^{1}  Bar/23* 14/9  eq: +0.391 (0.070) 
 Player: Opponent:  53.04% (G:16.50% B:2.55%) 46.96% (G:27.03% B:4.84%)  Conf.: ± 0.005 (+0.386...+0.395)  [0.0%] Duration: 1 hour 13 minutes 

3.  Rollout^{1}  Bar/23* 12/7  eq: +0.340 (0.120) 
 Player: Opponent:  50.61% (G:16.42% B:2.64%) 49.39% (G:28.69% B:5.39%)  Conf.: ± 0.005 (+0.336...+0.345)  [0.0%] Duration: 1 hour 14 minutes 

4.  Rollout^{1}  Bar/23* 7/2*  eq: +0.311 (0.150) 
 Player: Opponent:  47.13% (G:18.42% B:3.48%) 52.87% (G:31.67% B:10.18%)  Conf.: ± 0.005 (+0.306...+0.316)  [0.0%] Duration: 1 hour 24 minutes 


^{1} 5184 Games rolled with Variance Reduction. Dice Seed: 49207271 Moves: 3ply, cube decisions: XG Roller

......NACBRACS SUMMARY (5k rollouts, XG2 3ply checker with roller cube)
...... m[8 9203 7278 K353]......n[8 9153] (not diagrammed)
......+C[8 986 7175 K284]
......–C[8 988 7167 K267]
...... d[8 753]
...... s[8 961]
...... g[8 970 7120 K150]
Play Key: 8 = 8pt (bar/23* 13/8), 9 = 9pt (bar/23* 14/9), 7 = 7pt (bar/23* 12/7, K = Kill (bar/23* 7/2*).
Score Key: m = money (center cube), n = unlimited no Jacoby no beavers (center cube), +C = money owning cube, –C = money with Opp owning cube, d = dmp, s = gammon save, g = gammon go.
Nactation tutorial • explanation of nacbracs
If we advance White's 9pt and 8pt blots 2 pips each, thereby giving her good 4s (and softening the duplication of 61 and 62), Blue's decision to play "8" or "9" is much closer, in fact "tied" when the score is +C (money, owning cube) or s (gammon save).
The results for this variant are:
..... m[8 985] "<=5 ...... n[8 953] "<=5
.....+C[9 85] "<=20
.....–C[8 922] "<=5
..... d[8 923] "<=5
..... s[8=9] "<=20
..... g[8 918] "<=5
For this variant, detailed rollout results for +C and s can be found below.
Nack
1.  Rollout^{1}  Bar/23* 14/9  eq: +0.137 
 Player: Opponent:  52.60% (G:13.52% B:0.61%) 47.40% (G:26.10% B:1.61%)  Conf.: ± 0.003 (+0.134...+0.140)  [98.3%] Duration: 6 hours 02 minutes 

2.  Rollout^{1}  Bar/23* 13/8  eq: +0.132 (0.005) 
 Player: Opponent:  53.73% (G:13.29% B:0.58%) 46.27% (G:27.03% B:4.14%)  Conf.: ± 0.003 (+0.129...+0.135)  [1.7%] Duration: 5 hours 55 minutes 


^{1} 20736 Games rolled with Variance Reduction. Dice Seed: 46465363 Moves: 3ply, cube decisions: XG Roller

1.  Rollout^{1}  Bar/23* 13/8  eq: 0.449 
 Player: Opponent:  53.72% (G:11.28% B:1.15%) 46.28% (G:26.16% B:6.24%)  Conf.: ± 0.003 (0.451...0.446)  [56.8%] Duration: 5 hours 13 minutes 

2.  Rollout^{1}  Bar/23* 14/9  eq: 0.449 (0.000) 
 Player: Opponent:  52.44% (G:11.74% B:1.27%) 47.56% (G:24.90% B:3.24%)  Conf.: ± 0.002 (0.452...0.447)  [43.2%] Duration: 5 hours 05 minutes 


^{1} 20736 Games rolled with Variance Reduction. Dice Seed: 49207271 Moves: 3ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10, MET: Kazaross XG2