Check out: First Robotics

There are programs for elementary to high school aged kids with teams all over the country. There are local, regional, state, and national/international competitions.

I would look into the kits that VEX Robotics offers. Thry support multiple coding languages (including vex blocks, which is visual iirc), have a very wide selection of modular mechanical components, and I can vouch for their quality. They even run competition events to solve game problems using their robots.

I have a kit very similar to this sunfounder picar I built a couple years back, maybe something like this? You'll need a raspberry pi for it, but no soldering or anything like that is necessary.

It does support AI, though I've only used the OpenCV abstractions - it's up to you how much you want to integrate. The motors and sensors are adequate, it has no problems moving under its own force. The included test tools use a web interface, you can build additional functions on those for "desktop" support. And it supports Python or Scratch but I've never personally tried the scratch side of things.

Edit - I found an article that goes into more detail around building and programming experience of this specific model.

Get an adruino kit, one that comes with a bunch of different stuff along with the arduino. There's tons that are cheap and come with various motors, servos, relays, and other stuff like ultrasonic distance sensors. That's really the next step out of plug and play Legos and into real robotics. And just start with real code, that's fundamental knowledge of how things work. Its like saying I'll just give him a calculator then teach him multiplication later.