I've been to a good few games on, or close to, the Camino - Pamplona (Osasuna), Bilbao, Lugo and A Coruna.
Unfortunately for you, Deportivo La Coruna are playing away from home around the time you finish. I've been in the Estadio Riazor many times in the last ten years and would highly recommend it to anyone. Great location right on the beach - although in October, it will be cold!!!
Lugo is a great little city and if you had time to take a little detour from the Camino, this is where you should think about.
Ponferradina and Celta Vigo - not for me!!!
I've searched and found these games on about the time you're on Camino. Hope they help!
Deportivo La Coruna v Almeria - 28th September
Burgos v Coruxo - 28th September
Lugo v Osasuna - 27th September @ 16.00 CET
Ponferradina v Albacete - 28th September
SD Compostela (Santiago) v Celta Vigo 'B' - 5th October
Don't know when in early September you're starting, but Osasuna v Alaves is on in Pamplona on 6th September @ 17.15 CET