iPhoto 9.5 is now up on the App Store.
Note that it might be a couple of hours before it shows up on your App Store, depending on where in the world you are.
I tred to update and all I get is:
Failed to verify the preflight file. It is not signed by Apple. The application will be available from the Purchases page.
Not sure but maybe the server is overloaded.
Retrieving data ...