Is it possible to do day trips Reggio Calabria to Sicily such as to see the volcano mt etna etc?
Should be, you can get the ferry across. We used to fly into Reggio whenever we visited family in Messina. More recently we fly into Catania because of flight availability. We were in Messina 2 weeks ago and were joining a cruise from there after visiting family. We wanted to see Mt Etna and Taormina and we had about 6-7 hours between checking in with the ship and the boarding time in the evening. We booked a private tour through Tours with Mario and saw both in that time.
It's only possible via an excursion or car hire in Sicily.
Then either prearrange a tour or driver, or hire a car.
The only public transport to Etna is a once daily AST bus that departs Catania at 8:15.