September/October can be a great time of year in Scotland, as long as you're aware of the shorter days (if you're based in the US you won't be used to how much the daylight varies here). But the midges will be gone and the trail much less crowded.

You don't say whether you plan to camp or use B&Bs. If the latter, you still need to book (and may have slightly less choice than in high season).
Over 7/8 days you have a relaxed schedule and daylight shouldn't be a problem. You should also have time to look around and listen to birdsong and (if you're lucky) perhaps hear red deer roaring in the rut! Please let us know how you get on idc.
