Looking for a little advice on a hand from earlier today. MD Live was running a $65 (+$10 dealer add-on) 10k guarantee, 15k starting stack, 20 minute levels, rebuys through first 8 or 9 levels, ended up with over 400 entries.
Hand occurred during Level 3. Hero had played 3 hands, primarily a decent-sized one where he had AA, raised 100->700 over 5 limpers, got 4 callers and was still good at showdown heads-up on an iffy board. He likely has a pretty TAG image. Villain seems like a competent LAG and was observed opening his button and triple barreling pretty big with 65o on 985K9 board. Seems pretty solid overall, but capable of making moves.
Blinds at 100/200, Hero has a little over 22k, Villain has 14.6k.
UTG player limps, Hero is UTG+1 with
and raises to 800. Folds around to Villain in the CO who raises to 2100 (fun fact: this was the first pre-flop 3-bet at our table). Blinds and UTG fold, Hero calls (?
:?).
[Pot = 4600] Flop is

. Hero checks (?
:?). Villain checks.
[Pot = 4600] Turn is


. Hero checks (?
:?). Villain bets 3500. Hero calls (?
:?).
[Pot = 11600] River is



. Hero checks (?
:?). Villain shoves for exactly 9000. Hero... (?
:
?)
These probably aren't necessary, but each (?
:?) signifies a spot where a different line could've been taken. For instance, folding pre-flop and avoiding a big pot OOP against a decent player, or 4-betting small-ish with intent of folding to a jam. Maybe leading the flop with a "feeler", as transparent as that usually is.
Thoughts on (1) different lines as well as (2) river decision as played would be much appreciated. Thank you all!
Hand occurred during Level 3. Hero had played 3 hands, primarily a decent-sized one where he had AA, raised 100->700 over 5 limpers, got 4 callers and was still good at showdown heads-up on an iffy board. He likely has a pretty TAG image. Villain seems like a competent LAG and was observed opening his button and triple barreling pretty big with 65o on 985K9 board. Seems pretty solid overall, but capable of making moves.
Blinds at 100/200, Hero has a little over 22k, Villain has 14.6k.
UTG player limps, Hero is UTG+1 with



[Pot = 4600] Flop is




[Pot = 4600] Turn is






[Pot = 11600] River is








These probably aren't necessary, but each (?

Thoughts on (1) different lines as well as (2) river decision as played would be much appreciated. Thank you all!