The pedi dentist who evaluated my DD's tongue tie said when there is a lip tie that she can't slide her finger across that area while staying in contact with the gum. That's a good test, I think, for your DD.
My DD does not have lip tie, though she also doesn't flange her lip when nursing and it can be painful due to that. She does/did have a posterior tongue tie, though. With major pain, I'd suggest looking into that, as well, if you haven't yet. I was able to identify that her tongue was tied with the Murphy Maneuver, described here:
A classical or anterior tongue tie is much easier to identify than a posterior, but could still be missed if no one is looking for it. I have a friend who is an LLLI who was familiar with assessing tongue ties and confirmed it, as well as an "alternative" pediatrician and, finally, the pedi dentist. But I also put in calls to quite a few ENTs and pedi dentists who all denied the existence of posterior ties. Our regular pedi and an ENT we saw for something unrelated both missed it. It's certainly not widely recognized, though it does, I think, cause plenty of problems.
Here's some more reading on the subject:
It is absolutely possible to get these conditions treated, even at 9 months of age. However, from what I've read, it may need to be done under general anesthesia rather than local (my daughter's tongue was clipped with no anesthesia or numbing). Finding a practitioner to do it is definitely the hardest part. We eventually had DD's done with an experienced midwife. Other possibilities include a pediatric dentist, ENT, or oral surgeon.
Definitely confirm that they're familiar with the specific condition (i.e., *posterior* tie, if she has that) before you go in for an appointment. I was very frustrated to spend $40 on doctor we were referred to who told me she wasn't tongue tied at all.
We went to the MW later that day and had her posterior tie clipped, with clear and immediate changes.
I hope you can find help for your DD and your breastfeeding relationship.