KK situation facing check raise

[Jailblazers]

PokerStars 0.02/0.04 Hold'em (4 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Preflop: Hero is BB with K[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/club.gif[/img].
UTG calls, <font color="#666666">1 fold</font>, SB completes, <font color="#CC3333">Hero raises</font>, UTG calls, SB calls.

Flop: (6 SB) 3[img]/images/graemlins/club.gif[/img], T[img]/images/graemlins/club.gif[/img], 9[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">SB bets</font>, <font color="#CC3333">Hero raises</font>, UTG folds, SB calls.

Turn: (5 BB) 5[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2players)</font>
SB checks. Hero bets. SB raises.

Final Pot: 5 BB

Insta fold right?

Edit: This guy has sat down about 5 hands ago, and so far he's shown to be pretty normal. About 50% of players seeing the flop. I've been playing pretty TAG and I don't see him doing a check-raise with a Q of clubs or a set. Leak?