What is a good strategy for waking up kids who stubbornly refuse to get out of bed?
Stubborn kids in the morning are a pretty common concern that parents come in with. You can provide some natural consequences such as explaining "You know you are having a hard time getting up and that tells me that maybe you are tired and we need to move your bedtime back." Since most kids will not like that I would look for natural consequences to provide that motivation.
Also, clear expectations of what time they need to get up, what time you need to get out of the door and what needs to be completed in that morning routine can help as well. Catch them being good through that process and give them acknowledgement and praise. Also, provide a little bit of incentive when they get all these things done. You get to do this traditional privilege before we leave.
Sometimes we're going to have a stubborn child that isn't thrilled about morning. There's this tendency to create more time in the morning for them to get themselves together or they get lots and lots of warnings to get up. I would eliminate all of those and make your expectations clear about this is what time we get up and if they meet those expectations they get some privileges. If they don't then they receive natural consequences.