A9 in BTN vs SB 3-bet

highly spewy play from both players. only river is good i guess

what you're basically saying is "i have complete trash but i am soulreading his deepest thoughts out of dubious sample sizes and that's what his range is every time". it just doesn't work that way...
if you really have to play like this, pick some less bad equity to do it with

I do not like the preflop play. It is not ok to call the 3b with this hand when that deep. SB has all better Ax in his range.
On flop I will not bet. Prefer to see another card for free. When he xr we should fold. Even if he is on a bluff his Ax are better, pot gets huge and we have 2 outs if any.

Pre: I would fold A9o vs 3bet pre, and if you want to to fight back than it's much much better hand to bluff 4bet with. For calling I need AJ+ in this spot.
Flop: To say I don't think he 3bet 33 and 44 preflop is wrong. It's actually my standard 3bet SBvsBU. AA, KK, QQ are also in his range and he can decide to play all these hands like this if he saw you attack flop checks often. I'm folding in this spot 100% (I actually would' be in it 😜)
Turn: If he had value X/R on flop, there's no reason for him to check this turn, so now I would actually bet/fold. Yes, you have showdown value but there are so many hands in his range that have to much equity vs your hand. Actualy, almost every card except non hart 9 and A, could help him. He probably wont fold better hands, but there's so many worse hands in his range that will call, that I think betting should be best here + in most cases you get free showdown.
River: As played, I have no idea 😜. Probably fold. He can have some bluffs, but some eights as well. I think on NL2/NL5 players generaly don't bluff river enough to make this call profitable.
After checking spoiler: Put this guy in your fish list, make a pair and call him down but be prepared on big variance 😜

Why would you call on the flop after raised I dont know (if his action doesnt make sense for you - raise)

You should fold pre.
As played, bet the flop a little smaller and fold to a raise.

Pre I would fold. A9s is good enough to play, A9o is not.
OTF I can sort of agree with betting but you have to fold vs a raise.
OTR it is close. After he checked OTT his line looks more bluffy. So I guess it might be ok to call.

Double fold! Both pre and flop :-)