I was going to isolate if it had folded to me but the flat this guy made seemed fishy, i felt if i flat called I would be in a tough spot on the flop and an isolation is too risky with pocket 9s?

any input

pokerstars Game #13898925065: Tournament #69788360, $20+$2 Hold'em No Limit - Level III (25/50) - 2007/12/16 - 12:41:22 (ET)
Table '69788360 121' 9-max Seat #9 is the button
Seat 1: peps78 (5655 in chips)
Seat 2: Tomo0655 (5100 in chips)
Seat 3: BigBankrolll (5685 in chips)
Seat 4: Kapppri (820 in chips)
Seat 5: mazmania (6430 in chips)
Seat 6: JOANCHUMI (665 in chips)
Seat 7: MournIt (2730 in chips)
Seat 8: reduxmachine (3115 in chips)
Seat 9: Dionysius79 (2785 in chips)
peps78: posts small blind 25
Tomo0655: posts big blind 50
*** HOLE CARDS ***
Dealt to reduxmachine [9s 9d]
BigBankrolll: folds
Kapppri: folds
mazmania: folds
BigBankrolll said, "didnt know circus was in town"
JOANCHUMI: raises 615 to 665 and is all-in
MournIt: calls 665
reduxmachine: folds
Dionysius79: folds
peps78: folds
Tomo0655: folds
*** FLOP *** [Ah 2s 3h]
*** TURN *** [Ah 2s 3h] [5c]
*** RIVER *** [Ah 2s 3h 5c] [Jd]
*** SHOW DOWN ***
JOANCHUMI: shows [Td Kd] (high card Ace)
MournIt: shows [7c 7d] (a pair of Sevens)
MournIt collected 1405 from pot
*** SUMMARY ***
Total pot 1405 | Rake 0
Board [Ah 2s 3h 5c Jd]
Seat 1: peps78 (small blind) folded before Flop
Seat 2: Tomo0655 (big blind) folded before Flop
Seat 3: BigBankrolll folded before Flop (didn't bet)
Seat 4: Kapppri folded before Flop (didn't bet)
Seat 5: mazmania folded before Flop (didn't bet)
Seat 6: JOANCHUMI showed [Td Kd] and lost with high card Ace
Seat 7: MournIt showed [7c 7d] and won (1405) with a pair of Sevens
Seat 8: reduxmachine folded before Flop (didn't bet)
Seat 9: Dionysius79 (button) folded before Flop (didn't bet)