They have to start somewhere, and have to want to. Having the vague idea they want to program won't motivate them to crack books thicker than their wrist. Most people never learn this stuff, and they're only nine!

Whatever they begin with should be simple and interactive. Mindstorm(or whatever Lego calls it now) might do the trick and won't kill them. I learned QBASIC and even now still use it a few times a year to rapidly visualize something - drawing one graphical line in QBASIC is "MODE 12", "LINE (X,X)-(Y,Y),color". Name a "real" language which can do that without five times as much preamble!

Anyway, young also means sharp. They will quickly discover the limitations of whatever tinkertoy language you give them, and that may motivate them to learn something better. I hated that couldn't do STRING=print a,b,c in BASIC. But I found that feature in C as "sprintf", which ended up leading me to Linux, UNIX, Web Development, networking, shell, and my career up to now.