Thanks for the comments. Lots of good feedback being made. Here are my thoughts:
I do believe I made a mistake, but I don't think it was isolated to this hand. I believe my mistake was made prior to the hand rather than during it, or rather that my earlier mistake snowballed into me making another mistake in this hand. I think my primary mistake was not paying close enough attention to the player in the Big Blind earlier that day. I had been on my phone far too much, and just casually observing the players at my table. Somehow, I had convinced myself that this player was playing fairly straightforward poker, and that he wasn't really getting out of line much. I now feel as though this couldn't possibly be the case after having seen this hand play out though. At every point in this hand that he had a decision to make, he couldn't possibly have made a worse one. 99J5 is a very easy fold from the big blind to a steal attempt, and over-calling on a T33 flop with it, out of position, is very strong evidence that someone simply doesn't understand how to play this game at a very fundamental level. These should not have been difficult decisions for villain to make. It's rare to see someone misplay a hand quite this poorly in these Omaha tournaments. The guy on the button was probably paying much closer attention because he is a pretty solid player and I rarely saw him looking at his phone. He probably floated behind on the flop with his QQ hoping to see if we'd give up on the turn and/or get lucky by spiking a Q, which isn't a bad play. It's basically the same read as I had when I thought KK holdings were in his range. Plus, he had an emergency low backup. Had I called the BB's turn bet, he might have folded his AQQ6 (I certainly would have).
That said, I don't think I can find a call here on this turn, given the read I thought I had on the BB and the button. I think I'm making this fold 100% of the time in similar future spots where I believe my opponents to be competent thinking players. If I had previously picked up on how bad this player actually was, then I could maybe have found a call, but I would absolutely hate it if so. But even if I think he's that bad, I still might fold, simply because I don't think I'm giving up much equity at all here, and I'd rather just look for a better spot to put my chips in since it's a tournament. If it were a cash game and I knew he was that bad, I'd just call though. In which case, it's just a simple 'call and cross your fingers' situation. I pride myself on my ability to read players though. I think at least knowing what type of players you're up against is one of the most important aspects of poker, as your decisions should always be based on that info. This was one of those moments where I had to eat a slice of humble pie because I was wrong about the player in the big blind, despite having sat across from him for several hours by this point. And not just by a little bit. I suppose it's plausible that he had in fact been playing tight ABC poker all day long until this hand, and then like
@DrStrange said, he felt like he was super short and just had to make a move, there's certainly some merit to the idea that he may have felt that way, but I just feel like anyone capable of playing a hand
that poorly must have given off some hints somewhere along the way that I failed to catch because I had my nose buried in my phone. It wasn't quite a Robbi Lew level bad call, but it's certainly bad enough that you don't see someone play a hand
that poorly every day. At least not in these Omaha events.
It's also worth remembering that there are 23 remaining low cards that could fall on the river out of the 44 cards left in the deck, so I'm losing half this pot a little more than half the time even if I'm good. The pot is 13 BB and it's going to cost me at least 4 BB to get to showdown, and if the low falls, I could easily find myself getting squeezed and not even be able to make it to a showdown. I need to win at least 40% of the time just to break even here. Maybe more like 50% given my reverse implied odds and the likelihood of running into a squeeze.