Yes, you can have your luggage transfer from the Dolphin to Poly. No biggie. Either take your bags to Bell Services yourself, or call them and have them pick them up from your room. Either way, your bags willbe transferred to Poly around 3pm, when Disney goes through a Resort-wide luggage transfer dance.
Once Bell Services has your bags in the morning, you just go on about your day.
Your bags will get to the Poly sometime around 4pm. You will NOT have access to them prior to their arrival at the Poly. Bell Services will not deliver your bags to your room automatically (although it does happen occasionally). You must be in your room and call down to have them deliver your bags. Tipping is expected.
It's all very simple
Steve