Is using a roll film back on a 4x5 body considered large format photography?
Is using a 35mm film back on a Mamiya 645 considered medium format photography?
Which matters more, the tool or the image? From my perspective, MF = 120/220, LF = sheet film.

It's all just labels, really. The only time I can conceive where it's relevant would be if you were wanting to join a large-format users' group on the basis of owning and using a 6x9 folder. Depends entirely on their interpretation, not yours.