There is no reason why the TT scar will have to be high, What can happen, though, is that the circular hole made around the navel, which ideally will come off with the excess skin will not removed and have to be sutured, leaving a small vertical scar.
An alternative that may be possible would be to lift off the navel with the abdominal skin and fat, and reset it in a lower position. Sometimes this is a better option. All possibilities need to be discussed with your surgeon.
It would be a mistake to make the whole incision high to avoid the vertical incision.
When you are ready for an in person consultation, RealSelf has listings of surgeons in your area. You should consider cross referencing the listings from the The American Society of Plastic Surgeons (plasticsurgery dot org). A listing in the ASPS website assures you that your surgeon is not only board certified, but also is a member in good standing of the major plastic surgery organization in the U. S. Thank you for your question, best wishes.