Flat 3b sb vs bb w/ A9s

[Marshall28]

No-Limit Hold'em, $2.00 BB (5 handed) - Hold'em Manager Converter Tool from FlopTurnRiver.com

MP ($200)
Button ($200)
Hero (SB) ($482.30)
BB ($210)
UTG ($91)

Preflop: Hero is SB with A, 9
3 folds, Hero bets $7, BB raises $24, Hero calls $18

Flop: ($52) K, K, K (2 players)
Hero checks, BB checks

Turn: ($52) 4 (2 players)
Hero checks, BB bets $34, Hero calls $34

River: ($120) 3 (2 players)
Hero checks, BB bets $80

Total pot: $120

So villain is 3betting 12% vs steal in bb, we didn't have any history of me 4betting him just yet, so I wasn't sure A9s was strong enough to 4bet call it off here. Maybe it was, not too sure.

As far as postflop goes, I can't think of a hand he checks behind the flop yet value bets both turn and river. I certainly can have a hand like 88/99 that would call both turn and river. At first I thought villain may have had something like AQ after checking behind the flop, I would have expected him to bet AA/QQ/JJ though really unsure. His line doesn't make a whole ton of sense to me and I'm having trouble figuring it out. Thoughts?

[BigPapi]

It doesnt make a lot of sense to me either. I would assume he'd bet flop with mid/ high pairs, which would be almost the only hands that would bet turn/riv here. Ax hands could be checking behind flop, but would they bet again on river? I also dont see what he expects you to fold on that rivercard after you called turn. I dont know if he would go for such light value on river as AQ after your range is still quite strong. He's repping such a small range really the way this hand was played, I think I would call based on this.

[ATOTHEC101]

My thoughts are the same as yours and his line makes little sense. Would sort of help if you knew whether he was a decent reg or not, as I can def see him checking behind decent pairs to hide the true value of his hand. It's just that surely he knows this is a terrible spot to bluff not to mention the times he thinks he's bluffing with aj/aq and you get owned which makes it more of a fold in my eyes, I just shrug and fold.

idk I just see villain having 88 here or something
people just check in the weirdest spots sometimes

[Marshall28]

idk I just see villain having 88 here or something
people just check in the weirdest spots sometimes

then we might as well assume he has a K a lot also ....

thx.

[mixchange]

PF: I 4b or fold OOP with A9s

flop its just a spot where you get owned OOP on this board too much...
im just as confused as you are. But I can see him checking the flop with both air and AA or a K