Your pickup time will be around 1:15 or so. You are assigned to that particular bus, so you can't plan to take a later one. You need to be out at the bus stop, ready to go, about 15 mins prior to the time given. That time you are given is the time the bus leaves, not the time you should be walking up to the bus stop.....many have made that mistake.
You have a few choices...you can head to a park (I try to go to one that has early EMHs that morning) but you will need to start heading out of the park by 11:45, noon at the latest.
You could have a car service pick you up at the park...giving you a bit of extra time in the park. But, you would have to have been able to use RAC for your checked bags and then carry any carryon bags with you to the park.
Or...use a car service from the resort back to MCO...that would have you getting picked up around 2:30. But, a car service is going to be similar in cost to a cab....$50-60.