The plane designation (AA 2219 7M8-Boeing 737MAX 8 Passenger) I posted for the route was taken from the AA website so it should be easy to tell if it is your aircraft or not. It is on the MIA-SXM and return flights. The onward or arriving in MIA connecting flights do not seem to be MAX8 aircraft

It's a bit strange but all of the October MIA-SXM flights are like this " AA 2219 738-Boeing 737 " which is fine but the September flights I checked are on the MAX8