Here is another robot kit that gets your kids familiar with coding and robotics. The WeeeBot Jeep 2-in-1 STEM Robot has everything you need to build a line follower robot or jeep robot. It comes with a drag & drop graphic programming interface.
You can control the robot from your smartphone or with an IR remote controller. The kit comes with a 7*21 RGB LED Matrix, ultrasound sensor, line-following/light/IR/sound modules, and everything you need to get started.