Hi Sherri!
Always nice to speak with a fellow South Carolinian! There's no better place I can imagine a child spending their birthday than at Walt Disney World (even "Big Kids" like me-smile)! Then top it off with it being your first trip. Get the cameras ready because you'll capture many magical moments...
The first thing I'd recommend is when visiting any of the parks, stop by Guest Services so your son can get a free "Happy Birthday!" pin to where on his shirt. Most cast members (and many guests) are familiar with the pin, and watch him get showered with "Happy Birthday's!" here and there as you walk through the park.
In some cases, if the cast member knows before hand, they'll add a little magic by putting a balloon in the resort room with a small note, or give a little cupcake at the end of a meal. (Just need to mention this isn't guaranteed, but generally Disney does try to make special moments extra special).
As for the parks, you have to visit Magic Kingdom and the iconic Cinderella's castle. While there, take in a parade or two, and definitely get the Show Times brochure for the Wishes Fireworks show above Cinderella's Castle! Definitely a magical event!
At 8 years old, your son (and Dad) will love all the cool rides at Epcot. If you plan to stay at Disney for a few days, definitely get the Park Hopper.
Shoot me any additional questions if you have them, and best wishes for a magical time!