Villain was 30-20-4, I was hoping for a pre-flop 3-bet to my obvious steal. Turn scared me a little, but had to call the min-raise. Thoughts on river?

Full Tilt No-Limit Hold'em, $0.25 BB (9 handed) Full-Tilt Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

CO ($35.35)
Button ($31.15)
SB ($15)
Hero ($40.80)
UTG ($26)
UTG+1 ($31.40)
MP1 ($5.45)
MP2 ($25.55)
MP3 ($4.65)

Preflop: Hero is BB with A, A. UTG posts a blind of $0.25.
6 folds, Hero raises to $0.85, UTG (poster) calls $0.50.

Flop: ($1.60) 4, 9, 7 (3 players)
Hero bets $1.5, UTG calls $1.50.

Turn: ($4.60) 9 (3 players)
Hero bets $4.5, UTG raises to $9, Hero calls $4.50.

River: ($22.60) 2 (3 players)

????