The little guy was probably just extremely stressed and freaked out. Pillow-case travel is not something snakes are initially used to. Depending on how long your drive back home was, and if he was only in a pillow case with nothing tight to press against, he would be pretty stressed out and ready to strike/hiss at anything, which he did.
Next time you buy a snake/transport one, try putting him in a pillow case and putting that in a cardboard box close to the size of the snake's hide. That'll help keep the stress down and prevent a tagging when you take them back out.
As for out-of-tank v. in-tank feeding, that's up to you. I feed mine out-of-tank so that way I can clean the enclosure when they're feeding.