Overpair vs. unknown and scary board

Opponent just sat down, so no reads.

Can I call this river?

If he picked up a club draw, I'm dead. If he picked up a straight draw on the turn, why is he betting the river again? If he just has a pair, why didn't he raise on the flop? I was so confused, so I just called. AJ or KJ will ofter wait to raise on the turn here in microlimits. Maybe the turn was a straight semibluff, and then the river was a flush bluff?

I'm certain I'd call this against a TAG or a LAG, but most of my opponents are fishy. And this kind of betting from them means I'm beat.

PokerStars 1/2 Hold'em (5 handed) FTR converter on zerodivide.cx

Preflop: Hero is UTG with K[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/club.gif[/img].
<font color="#CC3333">Hero raises</font>, <font color="#666666">3 folds</font>, BB calls.

Flop: (4.50 SB) 4[img]/images/graemlins/spade.gif[/img], T[img]/images/graemlins/spade.gif[/img], J[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, <font color="#CC3333">Hero bets</font>, BB calls.

Turn: (3.25 BB) 9[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, <font color="#CC3333">Hero bets</font>, <font color="#CC3333">BB raises</font>, Hero calls.

River: (7.25 BB) 2[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets</font>, Hero calls.

Final Pot: 9.25 BB

[GoblinMason (Craig)]

Standard call down, in more aggro games anyway. I haven't played 1/2 6m so I could be wrong, but at 10/20 that is a very standard calldown against an unknown.