Many shows on property do not accept late admission at all like Festival of the Lion King, Frozen Singalong, etc. Your Fastpass window ends 10mins prior to show, but at 9 mins til, you are late and will have to go through Standby. Attractions it is 15 mins.
You have a hour to use it though so just plan on going at your time. Going outside your time can cause more complications depending on the attraction and situation.