yes you can.
however it stops at Swan/Dolphin, Yacht/Beach, Boardwalk, THEN Epcot.
My advice? if you are able bodied, and want to get there quick, get off at the Yacht/Beach club stop, and walk to EPCOT...you'll beat the boat.
Total trip - by boat - from MGM to Epcot is around 24 minutes I think. You can cut this in half by walking from Yacht/Beach.