8 year old won't stay asleep

I have an 8 year old daughter who has since she was a toddler, trained herself to wake up after everyone goes to bed to get up and play. We have tried everything we can think of. We have even moved her into our bedroom on a cot so we can make sure she stays in bed. We have slept in her room, we have sat up, we have baby monitors with alarms set up, we have door alarms, and she still does this at least once a week. The next day she is whiny, overly tired and generally a normal kid who didn't get enough sleep. We don't think it's a sleep problem, because she only does it when she has an intentional plan (new toys, book she wants to finish, etc) and we check on her before we go to bed. My doctor has put me on a bedtime because I am so exhausted and while that is not solely relating to her habits, it certainly doesn't help. I am at a complete loss as what to do next. via /r/Parenting https://ift.tt/2NLwZsD