It's probably worth mentioning, the 9 key sellers on the classifieds are all the same person as the 9 key seller on outpost. That is to say, they're all me.

I am considering raising the prices on them, I've had a few offers already and one promised sale (thanks, trade holds) despite the listing being open for ~7 hours.

A drop does seem to be in order, but to 10 keys would probably be more accurate.