This article recommends Scratch for 12 and up. Scratch is good for kindergartners and up. The Snap fork is more appropriate for older students: http://byob.berkeley.edu/
This article recommends Lego Mindstorms for ages 9-12 (and python and ruby). The average age of people who used to buy Lego Mindstorms was 28. The box recommends it for kids over 10. Lego has a robotics kit for younger kids called WeDo. I would not introduce python or ruby to a 9 year old, unless you want them to hate programming. Teaching programming for its own sake is a recipe for disaster.
And again it's missing so much. For coding robots to do things see sites like http://fightcodegame.com/ http://robocode.sourceforge.net/ http://www.nessbots.com/
For making games, I'd start with Scratch for < 13 kids, but for older kids see sites like http://www.playmycode.com/ http://pixieengine.com/ https://www.scirra.com/construct2