How are her naps during the day? At her age, she should probably still be having 2 naps per day, each roughly about an hour long, and sleeping overnight about 11 hours... for a total of about 13-14 hours of sleep. Some kids need more, some don't need as much.
If her going to bed at 9:00 works for your family, then by all means, go with it. However, it does seem a little late to me. Our 2 year old goes to bed at 7:00 and has since the beginning.
You might have to let her fuss a little bit when she wakes overnight. If she's really crying, then you can go in and rub her tummy and back to calm her down. Don't pick her up, and try not to say anything, keep it dark. You might have to stand there for a bit, but slowly remove your hand, and walk out of the room as she calms down. You might have to do this a few times.
Could she be hungry? Are you feeding her when she wakes up? Try upping the amount of food she gets at dinner time or offer a small snack an hour or so before bedtime. Our daughter used to have to "tank up" and eat a TON at dinner. We found the more she ate, the better she slept. When she wakes overnight, are you nursing or giving a bottle? You can try switching to a little water instead, if you don't think she's really hungry (if she's just waking for comfort).
All kiddos are different, so it's a guessing game. I hope this helps!