it's a live game to start off. playing 3-5 500 max bet. I limp middle position with A6hh, gets limped around by 5 people total, blinds call/check. flop comes:

Kh Jh 9d

big blind bets 15, I raise to 35, all fold, he raises to 75 I call. turn:

2d check check

river 2h

he bets 100 I raise to 250 he makes it 600. I tank called with my main line of thinking, who doesn't raise jj or kk in the blind? I guess it's possible for 9's full but it just didn't feel like that. Based on the flop action, the way he bet me he thought he had the nuts. I put him on q 10 maybe with the redraw.

Unfortunately for me, this guy gave no sign of being a good player, so in my mind, he would play q 10hh or even just q10 off as the nuts even on the board texture.

It all comes down to two things:

is the fact that he checked turn immediately narrowing his range to a set?

Would he ever 3 bet with a worse hand on the river?

his line is incredibly inconsistent with a set... some verrrrry strangely played K2 is perhaps his most likely boat here. it is my understanding that live players play river spots like this very tight, and bad players are capable of playing value hands in very strange ways, so i'm not thrilled about calling, but the previous action is so strange & so nonindicative of 2pr+ that i wouldn't be folding