That is going to be one long day for the Canyon so if your other free day is the day after the Canyon, you may want to just relax. Scottsdale Fashion Square Mall is nice and an entire new wing anchored by Barneys just opened.
If you want to be active and actually get out and do stuff, there is the Scottsdale Museum of Contemporary Art, Talesin West (Frank Lloyd Wright house that wouldn't be too far of a drive from the Fairmont Princess), hike Camelback Mountain, or if you want to venture into Phoenix, there is the Heard Museum and the Phoenix Art Museum.
Restaurants:
In Scottsdale, Bourbon Steak at the Fairmont Princess is supposed to be really good. It's the next on our tour of resort steakhouses in Phoenix/Scottsdale to try :) BLT Steak at the Camelback Inn and J&G Steakhouse at the Phoenician are both excellent and have really really nice views. Elements at the Sanctuary resort also has a great view and good food.
Not at a resort in Scottsdale - Olive and Ivy near the mall is solid. Marcella's at Fashion Square just opened and has a really good happy hour deal.
In Tempe, there is La Bocca on Mill Avenue and House of Tricks just off of Mill, so that could be an excuse to venture and walk around the ASU campus if you were into that.
In Phoenix, FEZ is really good. You could do lunch or dinner there if you go to any of the museums in Phoenix I suggested. Cheuvront, Postino, and Chelsea's Kitchen are all really yummy.