1. Face Detection, Dehaze, more local sliders, pan and zoom.. tonnes more.
2. 9.1 is the newest version of Camera Raw and matches 6.1 and CC.1
3. No. Dehaze and blacks and white in local tools are in CC only.
4. Pretty much, but it won't have the CC.1 features. Mine doesn't either.
5. If you want to watch a video on it, I talk about it with Jan Kabili for The Fix: http://thisweekinphoto.com/thefix-018-book-giveaway-lightroom-face-recognition-with-sean-m ccormack/
In a nutshell, the main difference relates to new features going forward. LR6 will always get updates for new camera models and bug fixes. Only the CC version will get new features.