So you're not much of a morning person? Turns out that if you do yoga in the morning you'll become a morning person.
Actually you don't even have to do a full yoga class. What you want to do is wake up early enough to give yourself time to meditate and stretch in the morning. The idea behind this is to give your mind time to relax before you beat it up for the next 8 hours at work. It also helps you manage your stress levels which will help you get on a regular sleep schedule. Once you're on a regular/healthy sleep schedule you will have less of a problem waking up early.