Derek was revealed to be the killer when he tugged his brow, like his sister, in court. But Bull was looking at Jules when Derek was being question when he tugged his brow. The camera cut from Derek to Bull after the tug, to which Bull then faced Derek. He couldn't have seen the tug.
Cable purposely hits the 8-ball (and others cheer when she sinks it), even though there are still stripes and solids on the table. In reality, she would have lost the game.