Lol this reply ended up being ridiculously long.

Ok, I was going to say A9o is a speculative raise (suited much better).. but if everyone else is tight then it's a good raise. This is a spot where you can manipulate your bet sizes based on the situations presented. I don't know if I told you my preflop standards yet, but I 4x from every position like you do, except cutoff and button I 3x. The reason for this is because you can steal with weak hands a lot from these spots, and most people will fold with the same amount of frequency to a 3x or 4x bet. If you can get away with stealing a pot by investing 25% less then it becomes much more profitable. In a spot like this where nobody is playing any hands, you can really just 3x this weaker hand preflop. It seems like a tell to 3x here with a weaker hand but again nobody is going to pick up on it - esp if they are huge nits.

The flop is another spot where you can manipulate your bet size. The QJ is fairly coordinated but it's a rainbow and overall not too wet. If you had something like AQ here you would bet .70 as a good bet. Since you just have A9 here you can bet .60 cents. The reason is again betting .60 and .70 is going to get you the same exact amount of folds/calls on this flop. We just want to bet .70 with AQ so we make more on our good hands and .60 with A9o so we lose less when they call/raise. Small differences but over hundreds of thousands of hands will really add up.

Also, on super dry flops like 883 you can even get away with betting .50 into .90 against players who are playing a ton of hands. Just be prepared to let hands go when you get played back at after betting small. It's tempting to think they are bluffing you b/c you bet weak, but just let it go.

Half pot river bets are generally value bets from the average player. I'd call with AJ here depending on my reads. Again if he is super passive then it's best to just fold weaker holdings. Also this river in general is somewhat bad because it completes a few straights.

Note how he made a 1/2 pot value bet on the end here. This basically tells us that he plays like a super passive monkey. I'd basically be folding anything other than a strong hand if this player ever raised me. This information is extremely valuable to know as long as you can play with strong self control. If we were to lead this river and get raised, anything under Qx would be an easy fold. Most players like this rarely bluff so keep that in mind too, but you may see a spot where he goes crazy and ends up having a weak hand.