I think that's completely fine.Worst offsuit ace I'd consider shipping here would be a8o, and that's marginal, we're still pretty deep, depends on how wide I think his range is, how often he'll call with worse and so on. (he'd have to be very out of line) If it's a suited ace I'd consider any, based on how wild I think he is, I'll do it if it's comfortable. And all pocketpairs go in. Important thing to realize so is that A9o and A8o are significantly worse than Ato.As played, having someone thats 3betcrazy + not so deep effective stacks(50bb) we widen our valuerange for 4betting from something like AQ+AJs+77+ to AT+A8s+22+  + maybe kq.With ATo I think shipping is by far superior than calling, since you do not flop draws often, and the T is often midpair or forms part of a hand that gives him a straight draw + 2 overs. If you call intending to fold to a cbet unless you hit a piece then I think he'll do quite well when 3betting you with something like qj kj. Or even stuff like 53s if he doesn't stack off w bad pairs, I think it depends on how well he plays postflop, which is probably bad. (chances are a 3betcrazy person will get it in with any piece and then spew off some with nothing). If he 3bets often it's hard for him to have a better hand plus it's very common he'll stack off way too wide, think Ax kj qj, you'll even see stuff like Jts Kto. So you want to widen your value4bet range for sure, they get it in with worse and you pick up a decent sized pot without having to flop something.I'd like calling instead of 4betting only if you have a specific idea of how to get out of line postflop. Like if you know he always cbets big in 3bpots than calling and just shipping over him could be better. Or if you know he cbets too often and will fold to a bluffraise than flatting might be a decent option. Or if 4betting is too marginal(for example we're too deep) but we do too decent against his 3bettingrange. Usually we lack this kind of information because we don't see that many 3bet flops as a caller. And it's most often best to just get it against their too wide range instead of giving them a chance to outdraw/outplay you. I think calling is mostly interesting against people that actually fold to 4bets a decent amount but cbet alot (especially if big). Still I'd rather have T9s than ATo to do that.You're specific villain seems to be just a 3b-monkey(3betfelting a9o for 50bb is way too loose), I'd expect him to 3bet like crazy (25% or more) with a merged range(a8 Jt suited stuff) and get it in way too deep way too light. Which means we shove lighter for value and can call 3bets for value with more hands(anything we can continue postflop +ev with like broadwayhands and possibly semi-decent suited connectors), depending on his 3bet-size, how deep we are and his postfloptendencies. Should be easy game, what I find more interesting is if and how we should adopt our openingrange on the button. If he does not have a decent calling range and you're opening to 2x you can probably open and fold to a 3bet with about anything because chances are he either doesn't play enough hands out of position (50%ish) or he 3bets so wide that you can valueship like crazy on him(I'd say top 25% or so) and he'll either fold too much or call of with very weak holdings. If he's got a decently wide calling range it's probably watered down, if he plays fit or fold and calls a decent amount opening semiwide might still be good. BUT if he's one of these guys that always gives action it's IMPORTANT to tighten up, say 65-70%, makes life a lot easier. Plus when we can expect a 3bet it can be a great move to limp everything we want to play but whats happy to get 3bet. Or open a limping a range in general to either strengthen or polarize your raising range (like raise top 50% limpfold bottom 25% unless you see he attacks limps very often, or limp hands that play ok in limped pots like Q7o T7o 95s so your raising range has hands that can standup to 3bets more often).Other thing I think is worthwile is 4betting to 1/3rd stacks or slightly more, 480 or so, and felting any flop instead of 4betshoving. 1)it tilts villain 2)villain can't know we're not 4betbluffing (against certain villains we might be) 3)villain can call this with dominated hands he'd otherwise fold 4)with time we'll get an idea of how often he's 3betfolding, which might enable us to 4betbluff(doesn't happen often but can happen) 5) we might gain the ability to 4betsemibluff. some villains call a 4betshove with stuff they just flat a 4bet with and c/f the flop unless improved like Ax Kx. 6) It probably widens his range for stacking off. People especially monkeys spazz out to this quite often, they call with 86o and shove any flop, stuff like that. happens A LOT with people that 3bet insane ranges.

if he's 3-bet calling u with hands like A8s+,A9o+, and PP 66+, and probably hands like QK,JKs+....
thats about 13% of total hand combos....
 idk i would have a more open 4-bet jamming range,..... dont be so tight with ur 4-betting range, now tht u see how loose he's calling u with... add hands like 99 into ur 4-betting hand range, since its still ahead of alot of villains 3-bet calling range.....no need to balance, like 4-betting small with QQ+ hands to induce, where i see alot of small-stakes HUSNG players make, and 4-bet jamm with weaker hand ranges like ATo..... just jam with hands like AT+,99+, where its all +EV vs villains calling range..... balance ur total 4-bet jamming range, thus making ur 4-bet jamm unexploitable vs this opponent....
if he 3-bets wide... then adjust ur style of play, and develop a limping style, and 4-betting hand range,  or just open less on ut button, thus punishing his light 3-bets vs ur minraises....
i would call with ATs, since i have more postflop equity with the added FD equity, ATo jam, i think u played it fine..... ill try to do a calculation for u to see the results, if i have time....