A fun easy framework for game-making is LÖVE. https://love2d.org/ You can show the kid some games made using LÖVE (https://www.love2d.org/wiki/Category:Games), do some of these tutorials (https://www.love2d.org/wiki/Category:Tutorials)...
Even if you don't know Lua, it's so easy to pick up (http://learnxinyminutes.com/docs/lua/). And figuring out a new language with the 8 yr old could be cool too.