I, like many people, are subscribed to the Technote RSS feed. Are you? Anyway, I just saw a reference on there to the Enterprise Vault 9.0.4 Release Details:
So I guess it must have landed, or be about to land on the FileConnect web site (I can't check because I'm not a customer).
Have a look, and of course, don't forget to read the release notes, and updates files for important information relating to the release. The release notes themselves are here :