Does moving the root of tooth take 9 months with Invisalign? (Photo)

Hi, I have been going to Invisalign consultations and getting dramatically different answers as to how long my treatment would take. One doctor told me it would take 9 months to shift my upper front teeth since the root is crooked and moving the root takes a longer time. Other doctors have told me it would take only 4-5 months and that my case is easy. I am conflicted and don't know what is more accurate.