Cracked screen

There is no way for us to answer that.

You will need to contact the store and make an appointment.

We have no way of knowing what their work load is or their parts inventory is like.

Genius Bar Reservation and Apple Support Options - Apple

If everything is in order with the parts and someone available to work on it immediately, it shouldn't take more than an hour. However, parts aren't always in stock and if there are work orders before yours, they'll be done first.