First boat leaves the resort at 10, so that would not be option for a 10 a..m. reservation.
It's best to avoid DTD as a transfer point when possible, especially in the a.m. Bus service from DTD to the resorts is unreliable before 11 a.m.
The closest parks to both POR & OKW are Epcot & DHS. Take either of those buses which comes along, and wait in the load zone at the park for OKW Resort. When you arrive at OKW, get off at the first stop, Peninsular Rd., and walk back across the bridge to Olivia's; it will save you a 10 to 15-minute ride thru the resort, and the walk is only a few minutes. Allow 1:15 ;travel time from the POR check-in area; it probably won't that long, but that assumes worst case scenario of 20-minute wait for each bus.
Taxi is actually a good option for this trip, as the resorts are only a 5-minute drive apart. Taxi cost will probably be in the neighborhood of $5.
When you finish breakfast, you can enjoy the leisurely boat ride to DTD, and back to POR at the end of the day. The boats run until around 11 p.m. Note that the OKW & POR boats dock at different locations at DTD; ask the boat captain for details when you arrive at DTD.