A river c/r bluff

[wuwei]

I tend to play a fairly straightforward TAG game, but I'm trying to find good spots to mix things up more. What about this spot? Villain was not very good, running 44/14/2.5 over 45 hands. It checked the river because it seemed to likely he'd call with some mediocre hand, but once he bet I considered how many hands he could have at this point that can stand a check raise.

Thoughts on the raise and the bet size? Can I get by with significantly less?

Poker Stars
No Limit Holdem Ring game
Blinds: $1/$2
6 players
Converter

Stack sizes:
UTG: $214.50
UTG+1: $181.05
CO: $364.65
Button: $205.40
hero: $192.10
BB: $170.40

Pre-flop: (6 players) hero is SB with 5[img]/images/graemlins/spade.gif[/img] J[img]/images/graemlins/spade.gif[/img]
UTG folds, UTG+1 calls, 2 folds, hero calls, BB checks.

Flop: 9[img]/images/graemlins/club.gif[/img] 2[img]/images/graemlins/heart.gif[/img] 3[img]/images/graemlins/spade.gif[/img] ($6, 3 players)
hero checks, BB checks, UTG+1 checks.

Turn: Q[img]/images/graemlins/spade.gif[/img] ($6, 3 players)
<font color="#cc0000">hero bets $4</font>, BB folds, UTG+1 calls.

River: 3[img]/images/graemlins/club.gif[/img] ($14, 2 players)
hero checks, <font color="#cc0000">UTG+1 bets $9</font>, <font color="#cc0000">hero raises to $50</font>