Its all about scale, and without an elevation of the exterior it is tough to tell. Help us help you.

How tall are you?

Why do you have a "10.5 ceiling height"?

Where will the house be located?

Don't do it. 8' (96") is the way to go. Width?

I have 10 1/2 ceilings with an 8’ door. Door has sidelights. I agree with strategery. I think 8’ is as high as I would go.

A 9' door will look off.

It depends on what other openings or doors you have in the space. Will it match some cased openings or a full wall of sliders?

I have 12 ft ceilings in the public rooms and our architect drew in a 10 ft high front door. I fell in love with the look before I realized it had to be custom made. It matches the height of the 10 ft high multi-slide doors that it faces when you walk in the door. My window/door guy tried to talk me into an 8 ft high door unit which would have looked silly in a house with high ceilings and large rooms. Also the door + 2 side lites is nearly 9 ft wide.

Look at the proportions and how they relate to the rest of the space. You didn't give enough information for anyone here to give you an educated answer.