With the parking situation at DTD being what it is right now, it's pretty inconsiderate, but you can.
Buses don't start leaving DTD for the resorts until about 10:00, so you aren't going to be able to get to the park until at least 11:00. And DTD bus service is not great at any time of day. Expect to wait quite a while for the bus both in the morning and on the way back at night.
I would really recommend just paying to park at the TTC.