Bam is a very handsome lad. Sounds like he has the spirt of a Savannah. If he loves to play fetch, take showers with you, go fur walks on a leash, open doors, cupboards, drawers, that are not Savannah proof, then yeah, if he exhibits Those traits, then yeah, he qualifies.
He does exhibit a Savannah like, boy belly shot, though, just saying. lmao.
^^^Boy, belly shot, Girl NOT!
When it comes right down to it, doesn't matter if he is or isn't S.V. He is blessed to have found you, and you are blessed with a grateful, exotic looking cat, that could otherwise be disposed of. You are a true humanitarian, and an obvious cat caretaker.
Please do continue to post pics and updates of Bam. Cats are Cats, and this is where all the best cats are at

And who knows, you may decide that Bam needs a Savannah Sibling, and one cannot provide any better quality, socialized kittens, than the Breeder Members here can.
Purrsonally I'd give the kid the benefit of doubt. Heck, can't prove he is, can't prove he isn't. I'd tell him, Yeah, Bam, Bam, my Man, you are Savannah at heart, and you own my Heart.!!!