My nearly 10 month old takes 2 naps a day.
But the total day time sleep she takes is from 1hrs 30 mins - 2hrs 30 mins, then about 11 hrs nighttime sleep is this pretty normal.
She is waking up early anywhere between 4.30am - 5.30am, I know its her teeth as she is teething pretty badly at the moment. I don't think is overtired, but she can go up to 4hrs after her last nap of the day, which I think is too much for her.