If Adobe Update Manager hasn’t taken care of this for you, you can do it manually by going under the Help Menu > Updates. Alternately, download the Mac update or Windows update from the Adobe site.
Adobe 9.0.1 Release Notes | Buy After Effects here.
There are many fixes in this update, including the Puppet Tool, the Illustratorlayers importer, the Exposure effect, and stability of 3D object layers from Photoshop. They’ve also added Red Camera support. Here’s a movie about that from Adobe TV.
