Calling preflop is a mistake - you are never beat by the BU and your hand is more than good enough to get in against CO. My preference would be to shove but guess I could be convinced to 3bet/call off instead under some rare dynamics which would generally involve CO being a maniac and BU being extremely bad, but even then I lean heavily towards shoving.

Flop - kind of a gross spot but I would fold. Somewhat depends on CO's competence - this isn't a board he should be betting all that often, but if he is and BU is aware of this there could be some shenanigans going on - but without a lot of favourable info I'd always fold.

That makes a lot of sense, thank you!

I agree with Daniel and I would just 3bet rip preflop. I don't like any other sizing, because I think the button would flat most times when the CO folds to your 3bet with the intentions of putting you in a difficult spot post-flop.

As played, I think folding on the flop is the play. Again, Daniel's analysis is spot on. How did the tournament end up?

I would defiantly 3 bet but not all in, you want to get value out of the 99, you are 4 handed, and are relatively deep. So yes if you 3 bet shove you will add to your stack, but I like 3 bet to 1.2-2.2, and then calling a shove if it comes. If you get flatted you play post flop. It helps define his range, you often take it down and also shows that your BB is not just up for grabs! On flop that came if you got flatted, I would lead 1/3 pot and again call a shove. In my option