I would be really careful with this one. At this age, you are setting the routine for the future. Think about what you want the kids doing in the morning when they are 10, 12, 18... That is the routine you should be working towards. It may be rough for a few months, but it will be worth the rough few months to instill the routine.
That being said, we move the wakeup time as needed to make sure everything gets done with a little time to spare. If things are rushed and stressed, I add 10 minutes on the start end...