I'd say fold. One question how many hands do you have on him? Get the feeling it's not that many? Also he's kind of looking a bit fishy. Your hand blocks TT but I think he could have JJ, QQ or even maybe KK in which case having those hands actually blocks them so not sure it's a better call with AT than those.

my default play would definitely be to flat this to a 3x CO open, but 3-betting is not bad.

I'd fold here for sure, and your reads only want to make me do it more.

No combo draws, and sets and two pair are easily in his range. I also think he has a slowplayed JJ/QQ a decent amount.

Unless he shoves some kind of weird pair+gutshot like T9, you're way behind, and even the hands you beat have decent equity.

+1 on flattin gpreflop...this spot would play way better in SRP i guess...as played i would fold turn, too for already pointed out reasons

Ya ok. Not a fan of flatting pre but idk probably ok. I try to flat as little as possible in the SB.

Say we have not so great postflop reads on villain but he s still playing ~30% in CO. Do we stack off then?

i like the 3-bet with ATs in general, since Most LP opening ranges are wide, such as SC,and broadways, where your still charging value by 3-betting a hand like ATs, where u dominate a moajority of villains broadway/ weak AX hand ranges. 

Default: Bet/Bet/Check 

             Bet/Check/Bet depending on how the board texture changes

On the turn im barreling 80%+ for value. Villain has such a polarized range, since the its a rainbow board. 

Basically what bluff is villain repping? with hands like 66,77,44,89s, in his 3-bet flatting range, i think this is more likely a fold. If villain is capable of jamming in hands like TQ,TJ,9T, then its a call, but in lowstakes player pool, its more likely we're facing a more polarized turn jamming range

its a fold, he is opening a very wide range and a single paired 10 is behind alot oif it.

Agree with the pre 3bet due to his high open frequency @CO.

Agree with the above comments about turn fold, as most ppl's turn shoves are way too unbalanced and value hands biased. For any value shove, AT is in terrible shape.