I think, the player with J9 got outplayed quite a bit in this hand. It reminds me of a famous hand, where Tony G got coolered by Vanessa Rousso. The hand is blind vs. blind, and after opening 65o from SB Tony is egging Vanessa to raise saying "if you raise it up, you build a big pot, and then you can get bluffed out of a big pot later".
And in my opinion this is exactly, what happened here. Rather than simply leading the turn, after the flop went check-check, BB decided to go for some fancy check-raise with his small boat. On the river he obviously had to go for value again, but when he then got jammed on for his tournament life, he went "of f..... this is not, what I was looking for", and then he bailed out.
If the fold was good from a GTO point of view depends on, how BB construct his turn check-raising range. But to me it seem reasonable to assume, it also contains 99 and KT for value as well as some bluffs, and in that case J9 is way to high in his range to bet-fold on the river. Bet-folding J9 basically mean, he only gets to showdown with 1 combos of the royal flush, 3 combos of QJ and maybe 3 combos of AJ, if these also played for a check-raise on the turn.
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