Overnight in Savannah off of I 95 with 10 year old.
you definitely could go into downtown savannah and find lots of intersting places....none of which are too far off of 95 (maybe 20 min).
Closer to 95 is Sam Snead's. Although the name has 'tavern' in it, it isn't a typical bar and your 10 yr old would be fine.
I assume you are going I-16 from Atlanta to Savannah? Where you are spending the night and how far out of the way you are willing to drive would help with recommendations.
I'm not too familiar with places on 95 south of Savannah but from the junction of 16 and 95, it's not too far out of the way to go on into downtown Savannah where you will find any number of good places to eat.
If you are willing to drive 15 minutes or so off I95 I recommend Sweet Potatoes for good Southern food at much more reasonable prices and less crowds that the other Savannah hotspots (e.g., Paula Deen).
We're heading down to FL as well but stopping in ATL. Hoping to get great dim sum while there.