pretty much everyone of them?
M3i Zero Sakura is robust in levels that the bar and all work, and sliding the icons leave no room for mistakes much. Also it shows last 9 games played if you so want
Acekard 2i has no bar but the scrolling is second best robust with touch, plus if your 9 year old only plays games, it will remember last folder you had open. It also takes the touch as "open command" only if you press the icon only (leaving less mistakes where games opens by touch when you did not want - happened to me on cyclo)
Both of there carts have their pros and cons. In end all carts have pretty much same king of base GUI (have a menu, show icons, shows name, scrolls) - But these two I know to be pretty easy to use, especially Sakura since it is so responsive (so if your 9 year old happens to know how to use a windows machine, or a ubuntu linux or Mac windows; she will know how to use Sakura system of M3i Zero)
That's my two cents