Overpair or overset?

CO is very tight and I put him on a high pocket pair. Unfortunately I don't have a read on UTG, which is a problem. What's your play here?

Party Poker
No Limit Holdem Ring game
Blinds: $0.25/$0.50
8 players
Converter

Stack sizes:
UTG: $53.85
UTG+1: $40.15
MP1: $19.87
MP2: $49.50
CO: $52.73
zook: $80.91
SB: $55.40
BB: $43

Pre-flop: (8 players) zook is Button with 5 5
UTG calls, 3 folds, CO raises to $2, zook calls, 2 folds, UTG calls.

Flop: 9 5 7 ($6.75, 3 players)
UTG checks, CO bets $3.5, zook raises to $7, UTG raises to $14, CO calls, zook ???

Minraising is usually a very weak play when the pot is small.

I wouldn't even think about folding this hand. You are very possibly behind, but without a read on UTG I would call here and play it all the way to the river.

Push

It is damn near impossible to tell (and definitely is in this case). That's why you just have to run with it. He could have limped Aces, have an overpair TT-QQ, or he could have 99 or 77 - you'll just have to pay him off in that case.

Now - if you had raised to $10-12 on the flop, and had then been reraised allin or something, you MIGHT be able to get away from it...even then, I don't think I've read of but one case of someone folding set over set around here, and it wasn't in a case like this.
I know I never have and I just live with it...

AI

Thanks for the reassurance. I pushed, both called, UTG showed 99 and CO showed AA. I sat out a hand and rebought in full.

I doubt UTG has AA here, since he limp-called preflop. Unless he's a donk who would either check raise two guys showing strength with a worse overpair or limp a hand like 86 or 95, then it's hard to put him on anything other than a set here. I'd still push unless my read was very strong that he wasn't a donk.