Flop call is good. Dont think this is a raise ever. You want to have a spade or a stronger straight draw to raise the flop.

I dont think he's capped on the turn, unless he plays very very straight forward. Your hand can bet now + river or xb turn + bluff river. Again, spades are better bluffs.

River seems fine.

Flop call good. Raise loose but fine as well.

Turn chief is right, you don't need to bluff this, but I would. Size looks fine, villain should XF thrash and weak pairs. I think most villains will be capped once they XC turn.

River seems like a good card to bluff, given that some bluffs hit a pair or a straight. We are mainly trying to make villain fold 8x and Tx. I would go potsize bet but your size looks fine. If villain calls you with 8x or worse you should make a note that he probably likes to bluffcatch.

Flop usually call, kinda weak for raising but you can raise it if you really want to.

You have medium strong outs on the turn, so it's not a time to bet big. Your size is good. Check back fine too.

River you can go with any size. Maybe not all-in but with J9 you could overbet a bit, or with QT you could bet pot size, or with T5 you could bet 2/3. Checking back river is fine as well, lots of hands bust, can't bluff every time.

Basically anything is fine. It's a frequency hand. If you always bluff like you did you are bluffing way too much, if you never do then of course way too little. You should try to make some useful read in hands like this. You said you think his turn check is weak/capped, that's a read, which makes bet turn + bet river better. If you trust your read you should always take this line here.