You are perfectly right. The fact that he didn't 4bet jam preflop I think is the biggest indicator he didn't have A K. The check on the turn though, it happened to me as an attempt to trap me since he had the nuts and was in position, might as well set it up. Also the jam on the river could be made to look like a bluff to make you call with top pair or 2 pairs, and then realise it was not a bluff, but a straight. But this happens rarely, it does happen but not as much.
Yeah I agree. Of course we can never say, that its impossible for our opponent to show up with a specific hand. So yes once in a while we will get shown AK or K9 here, and we will have huge egg all over our face. But hand reading is about trying to estimate, how much
equity we have against their entire range and not only the top of it.
In this situation we can surely discount AK quite a bit based on the previous streets, and K9o is a really loose call of a 3-bet, so thats also strongly discounted. Its pretty futile trying to put a player like this on an exact range. But if we plug this hand into Equilap and give him AKs and K9s as the hands, that beat us, and 98s-A9s, A9o as the chops, then we only need him to have 4 random combos of bluffs, before this becomes a call. And if he can show up with 83s, its not to difficult to find those combos.
The other thing, which is important to consider here, is the fact, that we checked back twice. Do we ever do that with AK or K9s? Probably not. And then we are folding 100% of our range, if we fold 9X to a river jam. Thats obviously extremely exploitable and not something we want to be doing, unless we are really sure, a particular opponent would NEVER bluff. And realistically we almost never have that read
