Hi Kimberley,
The Electrical Water Pageant usually follows the following schedule:-
Disney's Polynesian Resort - 9pm
Disney's Grand Floridian Resort & Spa - 9.15pm
Disney's Wilderness Lodge Resort - 9.35pm
Disney's Fort Wilderness Resort & Campground - 9.45pm
Disney's Contemporary Resort - 10.05pm
When Wishes Nighttime Spectacular is scheduled to take place at 9pm, the Electrical Water Pageant runs approximately 10 - 20 minutes later.
I would recommend that you confirm the time for the exact day of your visit at the Guest Services desk when you arrive at the Polynesian Resort as times are subject to change and inclement weather can cause cancellation of the pageant.
Wishing you a magical trip!