I don't know exactly why i didnt cbet the flop. Maybe i wanted to get some value from lower pockets.
At the turn I raised to get value from Ax or 99.
What do you think about the size of riverbet?
After he shoved I was of course commited right? I mean he can do this with AT or A9s or AK but any other high Ace (AJ/AQ) or suited Ace and TT could be also in his range. What do you think?

What is his standard opening size utg? If it is different than 3BB what do you think that means about his range here?

Is he loose or tight? If he's loose we could assume he had a hand like QJc or JTc that he turned into a bluff thinking you had a rag ace that made trips and doesn't want to fold or something like that. It's unlikely he would have AK here as you block all but one K and there's already 2 aces out there. He could possibly have AT, a lower PP but I doubt hands like 22 open utg and 33-88 probably dont call down here. He could have QQ and not believed your line. This is an interesting spot.

If you fold here though you're just too exploitable I mean folding kings full of aces is crazy unless you have some good like read on this guy. Interested to hear what he had.

OOP I would go for a much bigger 3bet pre, closer to 12bb. I think 8bb vs a 3bb open is tiny.
I think there are plenty of Ax hands which have to call you down and not many hands which can catch up. Because of this I'd look to play over three streets with almost even bet sizing. I think this means ~60% of pot on each street, being wary of a Q especially.

Basically, 3 bet bigger and cbet flop.

+1 except I'd go for a little less than 12bb, something like 10bb. Bet exactly 62.88% on every street to get his stack OTR if no Q or J appear.

Fish here, where does the number 62.88% come from? Must be some mathematical balance behind it right?

If you bet that exact amount over 3 streets, the river bet will be an all in. Of course the exact number isn't that relevant, you could bet 60% flop and 64% turn and no one will notice, but it's good to know.

I'd 3b more pre and would not raise turn once flop is checked through.

Bet/bet/shove. Checking flop might get you a stab from something weak but you're going to risk missing value later oop. Plus he's pretty polarised to hands that always fold and really strong bluff catchers, so you want to barrel into that range.

River sizing is awful. Just go all-in when you've got a pot sized bet left and he called a raise on the turn.

With the UTG open can probably presume a fair proportion of his hands hit that board well enough to call a raise so I wouldn't worry about loosing value in that spot in the long run
On the topic of the river in that you were probably committed from what was in the pot already and there are a lot of worse hands that will call a shove there.
Interested to hear about what he was holding