25NL Rivered flush on a paired board, makes me go hmmmm

[spector]

Our token villian here is 14/6/2.6 over like 2000 hands. I was calling here seriously hoping to see a smaller flush or a terribly played 9. The unfortunte possibility of a boat is still there but it would be a really really slow played one. Thoughts? I seem to be facing situations like this a lot lately I guess I feel like maybe I haven't been making hte best decisions.
Full Tilt Poker
No Limit Holdem Ring game
Blinds: $0.10/$0.25
9 players
Converter (http://www.neildewhurst.com/hand-converter)

Stack sizes:
UTG: $25.35
UTG+1: $24.75
MP1: $24.40
MP2: $42.60
MP3: $78.25
CO: $12.95
Button: $26.60
hero: $47.70
BB: $12.75

Pre-flop: (9 players) hero is SB with 2/images/graemlins/spade.gif A/images/graemlins/spade.gif
4 folds, MP3 calls, CO calls, Button folds, hero calls, BB checks.

Flop: 9/images/graemlins/club.gif 5/images/graemlins/diamond.gif 7/images/graemlins/spade.gif ($1, 4 players)
hero checks, BB checks, MP3 checks, CO checks.

Turn: 9/images/graemlins/spade.gif ($1, 4 players)
<font color="#cc0000">hero bets $0.65</font>, BB calls, 2 folds.

River: K/images/graemlins/spade.gif ($2.3, 2 players)
<font color="#cc0000">hero bets $1.9</font>, <font color="#cc0000">BB raises all-in $11.85</font>, hero...

[emon87]

He is agressive postflop. I'm calling every time.

[munkey]

I think a set from him would have raised the turn -I think he hit a smaller flush/bluffng the river and given his weak stack size I'm instacalling here.

he did check-call to river and you did bet the turn so this led me to believe he could have been flush chasing.

[Sir Winalot]

I would usually check again on turn, because if someone has a 9 they'll probably raise you off your draw and you miss a chanse to potentially win a huge pot against their trips.