B&M 3/6: Q9c versus weird turn check raise.

[Biggle10]

Pre-flop: (10 players) Hero is MP2 with Q [img]/images/graemlins/club.gif[/img] 9 [img]/images/graemlins/club.gif[/img]
UTG (Spewy lagtard)limps, 2 callers (Both Loose Passive). Hero calls. Rest fold which is odd because most pots were usually 7 handed or so.

Flop: 6 [img]/images/graemlins/heart.gif[/img] 6 [img]/images/graemlins/spade.gif[/img] 9 [img]/images/graemlins/spade.gif[/img]
BB checks, UTG bets, 2 folds. BB is getting ready to muck his hand so Hero calls with the intention of raising the turn? Good/bad?

Turn: (4.75BB) 5 [img]/images/graemlins/diamond.gif[/img] (2 players)
UTG checks. Hero bets. UTG raises. Hero ???

Additional thoughts on UTG: He has been snapped off a couple times tonight when stabbing at ragged boards. Several times he has raised turn/river and folded to 3/bet. Though generally I would say he's closer to a thinking player than not. He value bets well.

I'm at a loss whether to fold, call, or 3-bet as I can see arguments for all.