As much as I know SAS 9.4 comes now with it's "own" web application server and it is the only one supported. This one is now no more treated as 3rd party and therefore fully supported by SAS.
Having only one version of server to support will also allow for better integration. I'm right now installing SAS 9.4 - and it appears to me that installing SAS 9 was never as easy as with 9.4