We have only had our Larkin since Saturday so he's not quite 9 weeks yet and he has a lot of sleep during the day. He's definitely more bitey when he's starting to get tired - when he starts wanting to bite us rather than his chew toys is usually a sign he needs to start calming down.
On average, I'd say he's been sleeping for 2-3 hours after 1-2 hours of activity.
Following advice from this forum, and because we are up early, I'm looking for him to have at least 2 hours sleep in the morning, 2 in the early afternoon and if possible another 2 hours later on.
I would love it if someone would tuck me up in a nice cosy crate and let me sleep - I'm done in!
Good luck with your puppy.