| Preachertex |
This is what http://www.d20pfsrd.com/races/other-races/uncommon-races/arg-kitsune says on the subject (bold is mine):
Kitsune, or fox folk, are vulpine shapeshifters known for their love of both trickery and art. Kitsune possess two forms: that of an attractive human of slender build with salient eyes, and their true form of an anthropomorphic fox.
Physical Description: A kitsune has two forms—a single human form and its true form, that of a humanoid fox. In their human forms, kitsune tend toward quickness and lithe beauty. In all forms they possess golden, amber, or brilliant blue eyes. In their true forms, they are covered with a downy coat of auburn fur, although more exotic coloration is possible.
I am rather new to this, so I don't know if it is a reputable site for source material, but I have seen people use it as a source.
*edit
I believe this would mean they have a specific form they can turn into, that is their human form and no more. I do agree however that this is not how kitsune abilities are traditionally, where they could literally change (not just an illusion) into whatever they please.
*edit 2
I just read about the feat "realistic likeness" without that, you cannot change to imitate another human.
pardon my blabbering.