Thanks for your replies! I switched to the N9 from an Android 4 phone and never looked back. Just so much easier to use (for me) with a proper terminal, ssh-ing into it etc.

Ok, seems my problem is mainly that I do not know how to obtain the aegis_hack. There is the installer for the coderus trusted repo, which offers no options and just silently completes. Then everything else happens on the command line. I installed aegis-install, (also aegisctl and debinstall for shits and giggles), but no new system installer presents itself, nor does an aegis-dpkg binary end up in my PATH.