I don't think you are correct in all of your assumptions. He is going to have a MUCH larger range than that, and he is likely betting his entire range when it's checked to him on the BTN. It's an “adopt a pot” at that point, because the OR has basically said “I have pocket 9's and missed”. It's possible everyone else has missed this as well, given how hard you hit it. 

The first thing I'd address though, is your game plan for the hand.

“Basically im new to the table and recognize Btn, a high stakes mtt huge regular. So as mtt novice I dont want to 3b my hand and play it oop against him” This, right here, is not good. You can't base your decisions to 3b or not just because a good MTT player is involved in the hand. Doing this has set you on the mentality to player weaker vs this specific player, and that mentality causes you to fold vs him on later streets in a spot where it isn't right to fold. It even has you trying to justify the fold now that you are asking for help, without trying to justify a call. Essentially, you allowed yourself to level yourself out of the pot. I know exactly what this is like, because I had the exact same problem a few years ago. It was by far the biggest leak I've ever plugged. I know that may sound harsh, and I'm sorry if it is, but it's really the biggest problem with this hand. Right from the start you had yourself playing passively.

Now, onto the actual hand; I'm 3 betting here, pretty much always. It's early, we are deep and playing AQo 5 handed OOP is not going to be a fun time at all. Better to 3b and thin the field while adding some dead money to the middle. I can't say I will always be 3bing, but it will be the primary action here. Sometimes I will choose to slow play it so that I can take a more aggro line post flop. 

As played, I am check raising the flop 100% of the time. There is no question about this, ever. We have pretty much flopped the nuts here. Villain never has AA. Never has QQ. Can have 88, lots of flush draws, weak Aces, Queens, and pretty much everything else under the sun because there was so much weak action pre and it's been checked to him. He is very likely to bet with everything purely in an attempt to steal the pot. When we X/R here, we don't have to put him all in, but when we do X/R we aren't folding to his shove. A lot of times I am X/R to 3200 to induce his shove. If we X/R and someone behind us reshoves, then we can evaluate. That becomes totally player dependant, but usually is more weighted to the top end of their ranges.

Given that we flat the flop bet, 100% check shoving turn card. The K only gives him a few more hands that are beating us (JT and a very weakly played AK). He is still betting with a lot of his original range, as you have a lot of heart draws in yours. Even given his sizing on turn bet, if he's bluffing and you pick it off, he still has 25BB, which is nothing to worry about. So don't just take that as absolute strength. If he is semi-bluffing with his draws, he will likely call off to our x/shove and we will be in a great spot to eliminate this player from our table, and a small risk relative to our overall health. He isn't just bet/folding everything other than the nuts here. He is going to be calling with all flush draws, weaker Aces, KQ and such. He might even call with a Qx if he thinks you are bluffing. 

Short Version – Play less scared, and less protective of your “current stack”. This was a spot where you very likely missed a lot of value and a great chance to bust a tough oppenent, and it seems that's because he is a “really good reg”. Everyone is playing the same game with the same cards. The difference between you and a very good reg is the decisions that get made with those cards. They don't just magically have the nuts every time (well, some of them seem to…). Again, sorry if this seems harsh, I promise you it wasn't meant that way. I just wish someone had broken me of this exact thinking a long time before I broke myself of it.