($27) Leading with set in raised pot, turn play?

[EscapePlan9]

PokerStars No-Limit Hold'em Tourney, Big Blind is t20 (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

MP3 (t1950)
CO (t1490)
Button (t1430)
SB (t1370)
BB (t1260)
Hero (t1500)
UTG+1 (t1500)
MP1 (t1500)
MP2 (t1500)

Preflop: Hero is UTG with 3[img]/images/graemlins/heart.gif[/img], 3[img]/images/graemlins/diamond.gif[/img].
Hero calls t20, <font color="#666666">2 folds</font>, <font color="#CC3333">MP2 raises to t120</font>, MP3 calls t120, <font color="#666666">4 folds</font>, Hero calls t100.

Flop: (t390) J[img]/images/graemlins/diamond.gif[/img], 7[img]/images/graemlins/club.gif[/img], 3[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">Hero bets t200</font>, MP2 folds, MP3 calls t200.

Turn: (t790) 9[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets t450</font>...

I don't know what MP3 was calling with pre-flop or on the flop, but I'll assume he's just a donkey. What's my play on the turn? In retrospect I think I should have check-called incase he was chasing the flush, and also betting out could scare away many hands I can get value from with a river bet, or inducing him to bluff.