three barrel?

[n.s.]

12-24, 7 handed right now

CO is loose and very straightforward/passive. Earlier he limped UTG with Q8s, called my raise from UTG+1 and called down with a gutshot that he bet out when he hit it on the river.

SB is a young white kid. I don't have a strong read, but he seems like he is trying to play well, but is in a little over his head.

BB is a straightforward, tightish player.

PF: Hero is button with 9[img]/images/graemlins/club.gif[/img]T[img]/images/graemlins/club.gif[/img]
three folds, CO open-limps, Hero raises, both blinds call, CO calls.

Flop: K[img]/images/graemlins/heart.gif[/img]6[img]/images/graemlins/spade.gif[/img]4[img]/images/graemlins/club.gif[/img] (4 players, 8 SB)
SB checks, BB checks, CO checks, Hero bets, only SB calls.

Turn: 7[img]/images/graemlins/spade.gif[/img] (2 players, 5 BB)
SB checks, Hero bets, SB calls.

River: 2[img]/images/graemlins/heart.gif[/img] (2 players, 7 BB)
SB checks, hero...?

I can't win by checking, but should I just give up? How about the rest of the hand - misplayed on every street?