The Great Blasket boat tour runs until 1 October.  Prior to that, it can be weather-dependent, but if you are flexible with your three days, you SHOULD be able to make the trip.

September / October weather can be a dice-throw.  The past year, our visit was during the same time period and the weather ran the full gamut from bright, sunny (warm-ish) days, to dreary, blustery and wet -- although mostly decent, over-all.

We tend to stay a bit away from town center when we stay.  A personal favorite:   https://towerviewdingle.com/      but there are a number of excellent B&B options closer in.  

For info on the tour, see:  https://www.greatblasketisland.net/   

There is a coffee shop and self-catering rentals available on Great Blasket. Weather - as always - is unpredictable. It can be decent in Sept. One of the original cottages has been restored by the OPW and is now open to the public.

Lodgings to recommend in Dingle walking distance to town:

Tower View

Greenmount

Dunlavin House

Emlagh Lodge

Pax House

Right in town is Benners Hotel and Dingle Bay Hotel.