Hello - we're currently on Clearspace 1.3 and I'm looking through 1.9 for a possible upgrade.
One thing I just noticed in out test implementation of 1.9 is that users without moderator or admin privileges for a space still show "Delete document" in the Actions menu when viewing a document for that space. (If they go ahead and try to delete a document they get an "Unauthorized" message, however)
Yeah, it looks like the utility class responsible for computing whether or not someone had delete document permission returned true if the user had 'create document' permission. I filed a bug for this: