Hi Cynthia,
Our family will also be there during that week and I am happy to say that
www.touringplans.com ranks the expected crowd level at moderate.
Touring plans is an online website that utilizes a number of factors like past attendance, holidays and special events to rate each day on a scale of one to ten, with ten the largest crowds and longest waits. During that week, Touring Plans has ranked the days at five or six. The site also creates a table indicating the best and worst parks to visit each day. Based on their information these are the best parks to visit each day during your stay: 5th Hollywood Studios or Animal Kingdom, 6th Epcot, 7th Animal Kingdom, 8th Magic Kingdom or Hollywood Studios, 9th Epcot, 10th Epcot or Animal Kingdom, 11th Magic Kingdom, 12th Hollywood Studios or Animal Kingdom and 13th Epcot.
The Disney World marathon will take place over the 9th and 10th, with the Half Marathon the morning of the 9th and the full marathon on the 10th. Although the marathon does take the runners throughout the Disney World property and parks, you will most likely notice little effect on your park day. Full information on the race and the route it takes can be found
here. If you are concerned about an increase in crowds, head to Epcot. Since this park is the largest in size for guests to walk around, it often feels lees crowded than the other parks.
Hope you have a great time and be sure to say hi if you see me.