TORONTO — Sam Mendes’ “American Beauty” will have its world premiere as a gala presentation at the 24th annual Toronto International Film Festival.Starring Kevin Spacey and Annette Bening, “American Beauty” is a dramatic take on contemporary life in suburban American. The film also stars Thora Birch, Allison Janney, Peter Gallagher, and Mena Suvari. This is the first feature for Mendes. Pic is produced by Dan Jinks and Bruce Cohen and distributed by DreamWorks. The festival runs Sept. 9-18.