I've done some Scratch stuff with my 10 year old (he was 8-9 at the time). It is a good starting place for teaching some of the concepts like looping, objects, and messaging. If nothing else, it is a good way to visualize those, even if you turn to something like Python for "real work".
I would start by asking him/her what she/he wants to do. Pick the tool that fits best. Want to build a game? Start with Scratch because it teaches the actor-based programming that you want to use for games.
I would start by asking him/her what she/he wants to do. Pick the tool that fits best. Want to build a game? Start with Scratch because it teaches the actor-based programming that you want to use for games.
Hard to give more advice without more specifics.