I got my two girls when they were 10wk and for the first few months they woke between 2-3am and were back in bed by around 7am. Joeys sleep a lot more than adults, do you have him in a bonding pouch during the day? If you are waking him to bond with and give treats (as we all probably do) then that will probably affect how much he sleeps at night.
He could be a little sad, leaving the parents for the first time is scary, he's never been alone before. That's why we always suggest getting two. Even in a pouch around your neck he is still alone inside.
The reason he was probably up early last week was because it's a new palce and he may have been settling in, but joeys do sleep a lot longer. It's not unusual.