How do I know how my cat will react to me getting another cat?

So, my cat, Barney, the love of my life….would it benefit him if I got him a companion? He requires a lot of lovin each day, which is one of the things I love about him, and I try to give it to him when I can, but he still yells at me when I get home, even if I’ve only been gone 10 minutes! I was wondering if anyone could offer advice on how I might be able to judge if it would be good for him or not, before I buy another cat, obviously.

Background info on Barry: He’s 9, not very active, big needy snuggly boy. He sometimes freaks out when he sees other cats outside but when we were traveling last summer he met a few cats without it being a big deal so it really seems to depend on the situation. I want Barry to have a companion, but is that just wishful thinking? Is that possible? Would it help? Would he like it? Do you think a kitten might pump some energy into him, or would it just annoy him? Should I look for an older cat? Is female or male better? Any input, experiences, etc. is very helpful, I’ve never done this before and am not sure.

I should add that Barry is not the only reason I want a second cat, although for the above reasons I do think it could benefit him, I also just really love cats :D