The FAA web site states "We are currently processing permanent Airmen Certificates for temporary certificates that were issued approximately August 1, 2015".
So I agree with those who say it is possible she has passed her checkride and no one has come forward to tell the media that. It is very possible that she pushed hard and got it done just before heading off to school and was wanting to show off a bit to her friends and ran into trouble.
However if she had passed her checkride, I am surprised that no one has yet to come forward and correct the news reports. This could be done by her family, CFI, DPE or the FBO who rented the aircraft to her. So while I agree it is possible she just passed, I am a little doubtful based upon the lack of new information that corrects the initial reporting.
There is a high probability that she was known as a solo student by the FBO who rented her the plane but the FBO did not know she was illegally taking up a passenger. That does happen.
These are my thoughts exactly.....