I had my boy Beau neutered at 16 weeks, which is young but as my vet says if they're ripe, pluck'em
He'll be confused for a few moments when he realises he smells funny "down there", but at 4.5 monts his testosterone hasn't really had chance to kick in yet so he won't have had much time to think about females and the travel required to get them (I assume he's not out and about unsupervised just yet, he's a bit young to be out on his own).
If he's hyperactive, it's more likely to be his age and disposition than any wanderlust. My advice? Get another cat of the same age and with a similar disposition as a playmate, otherwise "Playmate" goes on YOUR nameplate, alongside "parent", "provider" and "poo clearer"
