Maybe just make a dog kennel-type outdoor enclosure for him (with wire over the top), and pop him in that when you go to work. If he seems to be acclimating well, you could perhaps transition him to free run (if he's neutered; intact cats should never be allowed to roam), but if he never really gets the hang of it at least he has his kennel so he doesn't wreck the house.
Is he already neutered? if not, could be the reason for the destruction.
Is he already neutered? if not, could be the reason for the destruction.