Eh, he’s just a little guy. Hissing is normal. But it’s a good idea not to let him get the impression that all he has to do is hiss and you’ll leave him alone. Our female kitten, Pepsi, did that when we first got her. (She was feral.) I picked her up every time. After a while she began to realize that 1) hissing is counterproductive, and 2) people are not evil predators (she’s still working on that one, though).
He has warmed up nicely and has spent alot of this evening resting and sleeping. He was a little demon this morning. Such a sweet little boy.
The hissing and meowing has calmed down too.