To reinstall the scenery, do a Remove first, then launch FS9, go to the scenery library, ensure the scenery has been properly removed from the list, then exit, and reinstall again.
At the end of the install, you might want to try reinstalling the stand alone Addon Manager, just to be sure, in case for any reason the Cloud9 installer put an older version (it shouldn't, because there's version and date checking in the installers). However, installing the Addon Manager at the end, wouldn't hurt in any case.
However, if the Addon Manager or the scenery weren't the last versions, you should have seen a warning about the scenery being an old version.
If you don't get any warning, it means the scenery version is correct (or it's not installed at all!). If the Addon Mananer says the scenery is active and there's no trial sign appearing at start, it's nothing related to activation.
If you see you don't have any double entries, this left only the option of another scenery, coming from something else, that is excluding DCA. However, it seems strange that both DCA and LAX are both excluded.