I noticed that on the STR-DA9000ES the Reciever itself requires that the "Input" button be pressed while the I/O button is toggled on, not the "Enter" Button like previous models.
I also could not change the AV1/2 on the Remote for this Reciever by using the above instructions.
However, after the Reciever is changed to the appropriate AV1/2 , you can use the "Register" feature on the Remote. The Remote will pick up the last setting (AV1/2) from the Reciever using the 2-way communication.