Is your Gallery application in the N9 not recognizing faces any more or it is not giving any more suggestions? Maybe you are suffering a well known bug. Just install Facerecognition Resetter Plugin and click on the “Protect” button. You want to do this even if you are not suffering this problem since this will prevent it from appearing in the future.

If you want to correct this problem or prevent it in the future, just check quickly on the announcement note:
http://blog.andresgomez.org/2012/10/...-the-nokia-n9/

More info:
http://igalia.github.com/gallery-plu...tion-resetter/

Br.