How Do i respond to the TURN BET

[Sightless]

i was totally confused by this hand, it happened in afternoon and I've been thinking about all evening in a College class, still have have no clue what to do...

BB is 38/7/.77 over 70 hands no other reads
Button is 21/10 not that many hands on him so AF is meaningless

Party Poker 0.50/1 Hold'em (6 max, 4 handed) converter

Preflop: Hero is UTG with 9[img]/images/graemlins/heart.gif[/img], K[img]/images/graemlins/heart.gif[/img].
<font color="#CC3333">Hero raises</font>, Button calls, SB calls, BB calls.

Flop: (8 SB) 8[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/diamond.gif[/img], 2[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(4 players)</font>
SB checks, <font color="#CC3333">BB bets</font>, <font color="#CC3333">Hero raises</font>, Button calls, SB folds, BB calls.

Turn: (7 BB) J[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">BB bets</font>, <font color="pink"> HERO!? </font>

[milesdyson]

i fold. button seems tight, so what is he coldcalling on the flop here other than 88/99/JT or some other slowplayed overpair? you think he will coldcall here with A[img]/images/graemlins/diamond.gif[/img]Q[img]/images/graemlins/diamond.gif[/img]? i doubt it.

Anyone clever enough to bluff here would be clever enough to check-raise you, I think. I'm guessing he paired his kicker, with something like J9/J8.

Edit: I think the logic in my first sentence is twisted and flawed. Please ignore it.

I do think this guy is too passive to bluff here, though if he were going to bluff, he'd donk rather than check-raise.