He's a cutie right enough, Tan.
No, he can't go straight outside, the anaesthetic makes them drunk and vulnerable for a good 12 hours so he really needs to be kept inside somewhere safe overnight after his op.
However, in my (extremely recent) experience, they tend to sleep really soundly after a good nosh, so he'd be fine on a soft blanket in a shed or garage, just for one night. You could pop a litter tray in with him but as long as he gets a good sleep somewhere safe he'd be fine to be set free the next morning.
If you don't have anywhere for him to sleep it off, why not ask the vet to keep him overnight?
I'd offer him a sleepover if I were a bit closer, but then I'd be forced to keep him! (OH says no, no way, absolutely no flippin chance lady NO .... hmmm )
My latest project Ivan has just been through his castration yesterday
and been set free this morning, he's still hovering around the back garden, wondering where he left his libido.
Hope someone steps up for Mr Blue, he's a real sweetheart.
Does he like girl cats? Thinking of Pav, and a little pal for Felicity. Well she did mention it