I guess I am going to be that guy....I disagree with all the folks telling you to cbet this flop. Here is my perspective on the hand.
The preflop raise is too big, no need to make it 3bb with a 20bb stack. We need to have a plan every time we raise - if our plan here is to raise/fold to any jams then 6k does everything that 9k will do for us and costs less. If you are committed to calling off then why not open jam?
Moving on - I like the check on the flop much better than a cbet. This board smashes the SB way more than your opening range even as wide as the button can be...if we cbet this flop and get jammed on do we really want to call it off with a straight draw and one over? We want to get our money in good...not when we are behind - so it's a shame here to get check-raised when we have a good draw and an Ace.
The check back on the flop will allow us to realize our equity in the hand without being check raised on the flop and over committing to a spot that you are likely beaten on and looking to suckout to win the hand...again, we want to be getting it in when we have the best of it...not when we are behind! What better
hands can we get to fold by cbetting this flop? Better Aces? They shouldve all 3bet us preflop unless they are super passive. Are 66s even folding this flop to one bet? So I think given this board we are only getting called by a ton of hands that are better than ours while hands we beat will still likely be beaten on the turn. Plus when we do cbet here and get called we only have one of two turn options - we either give up on the hand, or we shove and are likely getting called by straights, 10s, and or maybe even some sticky 8s and annnny 1 pair + straight draw combos. I would elect to cbet this board if one card was a K or maybe even a Q - but since that's not the case I would check this board back ALOT. We still potentially have the best hand here quite a bit and as I have said plenty already - it's a shame to open the door for us to be pushed off our equity on the flop.
So that all said lol - anyhow, when the flop goes check-check and our opponent leads the turn at best we have approximately 22% to win the hand vs a random range - that is, IF we are indeed behind in the hand - also by leading the turn our opponent allows us to fold cheaply - if they had J9 here they should be checking alot or betting small to try and induce bluffs from our ranges and get calls from draws and sticky Ace high combos. Betting pot here is pretty polarizing...pretty likely they have a made hand of some sorts, are confident their hand is likely good and are looking to stack off to any jams.
In conclusion- raise 2x preflop, 3x on 20bb is just too big unless we are definitely committed to calling off jams preflop - raise 2x, check back flop - fold the turn lead and move on. You only lost 2 BB, all the good $$ in MTTs is at the final table - so we should be looking to do all we can to get there!!
Hope this makes sense. Hope it helps. Take care!