So, you answered your own question. If the weak player is riding the 9 every chance he gets. Then the better player needs to neutralize that. And if he plays safe, pretty hard to ride the nine if you can't kick

Thus, the good player just stopped the banger from getting lucky. Sooner or later he's going to realize he needs to run out instead of banging the 9 ball in. Actually, folks are helping him, not hurting him. And if he eventually quits in disgust because he loses so much, it was never meant to be