To simplify what they're trying to tell you here, Go to Settings>Security>Developer Mode and turn it on, then the next thing go to: http://talk.maemo.org/showthread.php?t=80600 and download the latest version of QTweak... And finally in there choose option EE..

After you're done with all that your N9 will be fully open, I would then add community rzr's repository and other ones from N9QTweak option (II)..

Also search this forum for the amazing things that they've done for Harmattan..