[Froobert]

Hand 1:

Fold preflop, KJ can get you into trouble - especially against an agressive player. You're probably going to have to pay a lot to get to showdown since he bluffs when you check your marginal hand, and also he will sometimes have a real hand.

As played, I might raise the flop to see where I am, folding to a reraise.


Hand 2:

Don't really like 3-betting with J9os as you don't hit many flops that you're comfortable with. Another issue is that you have the fish in the hand, and it's not a great idea to try and bluff a calling station, wait for a better hand to take the fish's money.
If you really want to start 3-betting light, maybe try some suited connectors, though I wouldn't do this against people you have zero fold equity with.

As played, fold to the flop miniraise. He's not miniraising this flop with anything you beat, and he's never folding any Q, JJ, TT, A9 etc since he's a fish. He's also committed to the pot because even an all in from you is going to give him 3:1 odds to call.


Hand 3:

The huge check-raise on the flop will force any half-way competent villain to fold all hands you beat. (Also remember that he saw that you just called a raise then called a reraise preflop, which is often a pocket pair)
With a set here, I might sometimes donk-bet the flop to $7-8 if I was sure he has an overpair (quite likely). He will reraise you with overpairs and flush draws like AKh, then he will be committed enough to call your push.
With the way you played the hand, you got some value out of an AK continuation bet, but I think you lost a ton of value against overpairs.