pushing my spot ball in
This is a question of breech of contract. You weren't aware that he would trick you out of your spot ball. That wasn't understood when making the game so the rules are unclear and the game should stop until you clear it up. Obviously you're morally right. He's trying to get over, but he's technically not wrong either so start again and pick better opponents to play with. I hope the bet wasn't too high.
if you a playing for $$ and getting weight, in this case I was getting the 8, the other guy breaks, makes a ball but has no good shot, so he calls "push" and deliberately pockets the 8 ball.
Question is, does the 8 come back up?
This is a question of breech of contract. You weren't aware that he would trick you out of your spot ball. That wasn't understood when making the game so the rules are unclear and the game should stop until you clear it up. Obviously you're morally right. He's trying to get over, but he's technically not wrong either so start again and pick better opponents to play with. I hope the bet wasn't too high.