If you go after they reopen the bus stop at the Hospitality House, it will be the last stop before the bus heads to DTD. I'd say it takes a good 15 minutes to get there. Then you have to walk from the bus stop to World of Disney which could take another 10 minutes or so. And if your server is slow, you will have to really hustle. The buses come about every 20 minutes. So you would have to make sure you didn't miss the bus that will get you there on time.
The boat doesn't start that early, so you can't take the boat. Plus the boat lands at Pleasure Island, not at the Marketplace, so you have little hike to get there. I think the boat runs 10AM to 10PM and it leaves every 20 minutes. So you would have to get a boat by 8:20 to make your appt.
What about your resort?