Can a template form calendar slide be edited

Also, can a template form calendar slide be edited
to instead show months, no days, e. g. Sept through June?

If I understand correctly, you were referring to the Appointment field in the form.

Currently there is no option to customize the calendar display of the Appointment field.

But if you were looking for the functionality to limit the available dates, what you can use is the Limits option.

You can set the start/end date of the Appoinment avaliable.

Let us know if you need further assistance.