I'm jealous and I just got back 3 weeks ago!
I love September as a time of year for the walk and have had good to great weather for 3 years on the trot - this year I started a week earlier (leaving SJPdP on 15/9) and hit one of the busiest periods and was one week later than a heat wave that had passed through the Meseta.
Although busy, there was always room to be had in the municipal Albergues which couldn't be booked ahead and I found I walked so that I could start looking for a bed about 2pm which also gave me a good wind down.
Enjoy the life changing experience and your Camino Family when you get there.
If you are near the Blue Mountains in Australia we meet for a Pilgrim dinner and great conversation on the last Friday of most months and you would be most welcome - facebook "Bluemountainscamino"
Enjoy planning it and give yourself plenty of time to do the walk.
Tony