Years ago when I rescued my male (Boo), approximately 4 months later I rescued a 5 week old kitten (Puddy). The first thing my vet told me was to never allow unsupervised time between the two of them b/c full grown male cats will more than likely try to kill a kitten. Boo has always been a gentle cat and Puddy was quite the terror, so I thought it might be the other way around. LOL However, I didn't want to take a chance that Puddy might be hurt b/c she had many physical problems as it was, which is one of the reasons I rescued her. I waited 8 weeks before they were allowed to be alone together; I gave them time to get to know each other a little at a time. I've never forgotten my old vet's words and whether or not they're true I can't be sure. Cats are all different just as are humans but I'd err on the side of caution if I were you. I certainly don't want to alarm you but you've indicated that there are signs that the two of them might not get along and it may just be play but you should supervise their time w/each other regardless.

And welcome to Pet Talk!