UTG is an unknown short-stack.
MP1 is terrible, probably even worse. Runs good though. What else is new. Full Tilt calls it variance.

Preflop I'm looking to isolate MP1 and then control the pot size in position. Once I flop top set though, did I overplay by thinking I could push out UTG if he had a bad flush draw? I mean isn't a practical to think that a 2 and 3 on board would likely counterfeit his low draws?

$0.25/$0.5 Pot Limit Omaha Hi/Lo
9 players
Converted at

Stacks:
UTG ($15.00)
UTG+1 ($49.70)
MP1 ($92.25)
Hero ($30.05)
MP3 ($39.00)
CO ($50.00)
BTN ($53.25)
SB ($20.95)
BB ($23.75)
[CO posted $0.5]

Pre-flop: ($1.25, 9 players) Hero is MP2 [Ah][9h][Ac]
UTG calls $0.5 ($14.50), 1 fold, MP1 calls $0.5 ($91.75), Hero raises to $3.25 ($26.80), 5 folds, UTG calls $2.75 ($11.75), MP1 calls $2.75 ($89.00)

Flop: [9d][3s] ($11, 3 players)
UTG checks ($11.75), MP1 checks ($89.00), Hero bets $11 ($15.80), UTG goes all-in $11.75 ($0.00), MP1 calls $11.75 ($77.25), Hero calls $0.75 ($15.05)

Turn: ($46.25, 3 players)
MP1 checks ($77.25), Hero checks ($15.05)

River: ($46.25, 3 players)
MP1 checks ($77.25), Hero checks ($15.05)

Final Pot: $46.25

given your read, i think you played this well. fwiw, i don't really like this pfr _as a general play_, but it's ok to isolate a donator.

on the flop, fine. whether to bet the turn depends a lot on reads. if he's a cs that will call w any flush, then take your free card. if you can bully a bit, then try the turn push.

regarding the counterfeit -- yes, you often can bet people off counterfeit lows, but A24x and those type of hands are not uncommon. similarly, the nut flush draw is out there, and donks will often chase. when he doesn't bet turn and river, then i guess he does not have the nuts. how to progress depends on what you put him on for hand range and calling range.

Results if anyone cares:

$0.25/$0.5 Pot Limit Omaha Hi/Lo
9 players
Converted at

Stacks:
UTG ($15.00)
UTG+1 ($49.70)
MP1 ($92.25)
Hero ($30.05)
MP3 ($39.00)
CO ($50.00)
BTN ($53.25)
SB ($20.95)
BB ($23.75)
[CO posted $0.5]

Pre-flop: ($1.25, 9 players) Hero is MP2 [Ah][9h][Ac]
UTG calls $0.5 ($14.50), 1 fold, MP1 calls $0.5 ($91.75), Hero raises to $3.25 ($26.80), 5 folds, UTG calls $2.75 ($11.75), MP1 calls $2.75 ($89.00)
25.60% (EV = -$0.43)
31.80% (EV = $0.25)
42.60% (EV = $1.44)

Flop: [9d][3s] ($11, 3 players)
UTG checks ($11.75), MP1 checks ($89.00), Hero bets $11 ($15.80), UTG goes all-in $11.75 ($0.00), MP1 calls $11.75 ($77.25), Hero calls $0.75 ($15.05)
59.90% (EV = $15.95)
2.40% (EV = -$10.64)
37.70% (EV = $5.69)

Turn: ($46.25, 3 players)
MP1 checks ($77.25), Hero checks ($15.05)
77.80% (EV = $35.98)
0.00% (EV = $0.00)
22.20% (EV = $10.27)

River: ($46.25, 3 players)
MP1 checks ($77.25), Hero checks ($15.05)
100.00% (EV = $46.25)
0.00% (EV = $0.00)
0.00% (EV = $0.00)

Final Pot: $46.25
UTG shows: [8h][7d][5s]
MP1 shows: [8c][6h][3d]
Hero shows: [Ah][9h][Ac]

UTG wins $43.95 ( won +$28.95 )
MP1 lost -$15.00
Hero lost -$15.00