Not sure about the particulars at Wyndham Bonnet Creek, however, any ECV rental vendor you choose will have that info for you regarding drop off and pick up. Just call your preferred vendor as soon as your plans are confirmed to rent the ECV, and you can ask them all about their procedure at the Wyndham.
Main thing I would stress is to make sure you take the
scooter battery(s) in to your hotel room every night, and charge it completely. That way you don’t have to worry about constantly searching for electrical outlets, and spending your day trying to charge up enough to get to the next thing to do. You may wish to make sure that you know how much that battery weighs, and make sure that a member of your party could carry that the equivilent length you might have to walk across the Resort to get to your room(s); batteries can be very heavy, and could take as much as 8 hours to fully charge (depending on the battery chemistry and capacity.)
I’m guessing you will be flying in to Orlando? If so, remember that any mobility device that your husband chooses to bring from home will fly for free on all domestic US carriers, and can be gate-checked; just ask the gate agent for assistance when they show up to work the flight. So, that could be a wheelchair, or a scooter - or even a Rollator. When I travel, I take a Rollator so that even the few steps I take in the hotel room I can be safe and supported.
If he is bringing a personal device from home (remember that MCO has looooong TSA lines and most airport terminals are, by design, just a bunch of long hallways) you can protect the device with something like Velcro OneWrap (to hold it together) or a case or cover from
Amazon.
I know it all seems so overwhelming, but things will sort out as you go along. You can also call the front desk or bell services at the Wyndham, and ask them for information on specifics regarding on-site delivery of a rental scooter; that way you get it directly from the hotel.
I know y’all probably have plans for how to deal with issues surrounding his MS in the Parks; just a reminder that First Aid stations at every Park will be your friend. If he needs to lie down for a bit, or has other medical assistance needs, First Aid at WDW is fantastic. Each of the 4 Parks has a First Aid station, and you might want to find those on the map, and make sure you know where they are in advance.
One last tip: if he gets cold easily, he may actually feel “wind chill” from sitting on the scooter as it moves - even at walking pace. I carry a lightweight blanket and gloves, as well as a pack or 2 of “Hot Hands” when we leave the hotel, especially if we will be out at night at WDW. My family did not believe me until they experienced it for themselves; when you are physically walking, you exert enough energy to help keep you warm, but just sitting in a chair or scooter, you can chill quicker, especially if you are prone to being cold anyway. It’s especially a problem for me any time the temps drop below about 72 degrees! If he doesn’t want a blanket, he can always pop a poncho on, and that will help protect from the wind as well.