Am I missing something here?

Level III of a Stars $11 MTT. Started about 1450, down to about 800. I got my stack up early with AK when the flop was KK7 and got some guy to commit with K4. I slowplayed the hell out of that hand. I wasn't quite sure what to do with flopped trips, no kicker from the BB with four other limpers, so I felt like I needed to bet to figure out where I was.

PokerStars No-Limit Hold'em Tourney, Big Blind is t50 (9 handed) FTR converter on zerodivide.cx

Button (t1795)
SB (t3075)
Hero (t2970)
UTG (t4473)
UTG+1 (t755)
MP1 (t3052)
MP2 (t2210)
MP3 (t2775)
CO (t4310)

Preflop: Hero is BB with J[img]/images/graemlins/heart.gif[/img], 3[img]/images/graemlins/club.gif[/img].
UTG calls t50, UTG+1 calls t50, MP1 calls t50, <font color="#666666">4 folds</font>, SB completes, Hero checks.

Flop: (t250) 9[img]/images/graemlins/diamond.gif[/img], J[img]/images/graemlins/diamond.gif[/img], J[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(5 players)</font>
SB checks, <font color="#CC3333">Hero bets t150</font>, UTG folds, <font color="#CC3333">UTG+1 raises to t300</font> Hero ?

At this point I wasn't sure what to do. I know I'd feel just disgusting if I folded trips to a miniraise, but I was either dominated or way ahead. Do I just go ahead and push 30% of my stack praying he calls with A9?