He looks like such a sweet boy. I'm very happy you're taking him in and giving him a safe and loving indoor home.

So, I'm immediately thinking of Beren, the hero who lived as an outlaw in his own land for years after his people were betrayed and who finally fell in love with Lúthien and took a Silmaril from the iron crown of Morgoth to appease Lúthien's father, Thingol. He, too, had a hard life but wound up in a pretty good place in the end. Plus, "Beren" is short and easy to say, and it sounds a bit like "bear" (think cuddly teddy-bear), and I think he looks like a Beren. {= )

For similar reasons of "survived living rough for a long time and found love and happiness in the end," you could also choose any of Aragorn's many names, or just Ranger, or maybe even Dúnadan.

A Hobbitish name could suit him, too, since they're all about a life of simple pleasures such as food and friends (but are also very tough when they need to be). Bilbo, Frodo, Sam, etc.

That's a few thoughts to mull over, so I'll leave it there for now.

~Neshomeh

He has big Theoden energy. That's a very Theoden cat, especially from what you said about his past.