You can check in very early...as early as 7am!! The computers do a backup thingie or such around 5:30-6am, so that makes it hard to check in. But, if you arrive any time after 7, you should be golden.
If your room isn't ready, you can leave the bags in the car, or give them to luggage assistence and they will hold them for you.
With you arriving closer to 10am, you may be able to actually get into your room. I've been able to get into my room before noon at least 50% of the time.