Tuscany swim pools in Oct

I would think pool season is done by Oct. We had a pool in Northern California that had similar weather to Tuscany, and 3rd week in September was the latest we used the pool, and that involved heating it. Very unlikely any place would spend the money to heat pools. But you can always email the property to ask if the pool is available and or heated.

You may have already done this, but if not, you'll be glad you carefully checked the weather: at this time it's way too early to get a weather forecast but you can look at past years weather averages for Tuscany mid-October. Then within about 10 days of your time in Tuscany, you'll be able to get actual weather forecasts instead of averages.

Just so you have realistic expectations about the likely weather there at that time.

Most of the agriturismo list the opening and closing dates for their pools.

And even if pools were open, they would not be heated!
We had a villa in Umbria one year with a pool.
It was baking in Rome, and when we got to this villa, it was chilly at night, and the pool was so cold we had to force ourselves to go in just to say we had!
It was mid September.

I visited Tuscany and Umbria in late September- Mid October (2017) and the pools I saw were already empty at that time of year.

When I arrived to Rome, it was still warm, and a refreshing pool would have been great, however, my hotel didn’t have one.

As someone else suggested, it’s best to contact the places where you’ll be staying and ask them if the pool will still be open.

Enjoy your trip!