Yeah, the best strategy for Kemba is simple...
give him all the help he needs to rehab this summer, look for trades that help the team, let his agent sound out situations too.
If neither side can find a good trade, then you go into the season and hope he plays well.
Kemba isn't opting out because you bench him, he'll just demand a buyout, and if you don't give it to him the whole league including your stars and almost as importantly every agent, will think you're an unreasonable asshole.
Kemba got hurt. That sucks, but trying to bully him into not picking up his option is such a violation of norms that it truly far more than something like IT in giving a negative perception. It would send a signal of..... this is a clown franchise, never ever sign here if you can help it, if you can't, get out as soon as possible.