I would visit the Festival but for lunch/early afternoon Monday-Thursday.
For an eight year old, it would be a wonderful way to introduce him/her to the different foods each country traditionally eats. What I usually do is find the menu posted online (later this month), then research each dish and if there's something I want to try, I highlight it on the menu and make sure I try a piece of food I'd probably never get to enjoy.
The times I've mentioned shouldn't be busy at all.