It's a few years since I have been at that time but it was very quiet, there were still quite a few bars and restaurants open though. Weather wise it was mixed still had a few hot days sunbathing on the beach but had a few showers too. Night time temps I didn't wear a jacket or cardie but then again I'm from Newcastle and we never wear coats etc to go out!!!. But to be on the safe side I would take something. I would go back at this time of year, we were there in July this year and it was uncomfortably hot.

We havent been to Kusadasi for years as we now go to Icmeler in October.
What we have noticed though is the resorts seem to be closing earlier and earlier each year.
Last year the apartments we were in closed on 10th October and the year before the hotel closed on 19th.
As the schools dont break up until 26th October I dont think many places will be open then.
The Antalya area is an all year destination as its warmer so there will be more places open here.