Bump supported SDK to iOS 9.

Authored by featherless on Mar 15 2017, 1:49 PM.

Description

Bump supported SDK to iOS 9.

Summary: We'll investigate iOS 8 support after we cut v1.

Reviewers: O2 Material Motion, O4 Material Apple platform reviewers, Material Motion, chuga

Reviewed By: O4 Material Apple platform reviewers, chuga

Tags: Material Motion

Differential Revision: http://codereview.cc/D2878