Technically a 14 week old puppy shouldn't have a problem being in a crate for 5 hours. It's about the limit they can hold their bladder so just make sure he does his 'business' before you put him in. On the other hand.. He may not be used to being in the crate that long and would be happier 'caged' in the kitchen.
If it was me... I'd "err" on the side of him not destroying your house. You know he's safe in the crate, who knows what hell get into in the kitchen. An unhappy puppy is way better then buying new cabinets or him getting into something he shouldn't and be hurt.
Kevin (15 weeks old.. today!) does 4 hours in the crate every morning after the kids leave to school... He's used to it though.. He gets a bit cranky without his morning nap
Hope everything goes well for your son!