"she tells me that she used to crave emotional meaning and suffering in relationships etc in the past (but she's completely not like that now)....she had a million lovers and strange stories etc...can someone's enneagram change with time?"
Borderline personality disorder. This is normally outgrown and has nothing to do with the enneagram. However, enneagram type can change, that's why the enneagram itself has lines. There is also movement up and down the levels of development.
If she's not primarily a 6w7 then I would go with 9w8.