I'm a fan of the BBC micro:bit. The basic board is very inexpensive but comes with a lot of possibility already soldered in. You can choose among several well-supported programming languages, from Scratch on up to C++, so it can grow with you for quite a while.
There's not really an official robotics kit that I know of, but there are several 3rd-party options on the market.
There's not really an official robotics kit that I know of, but there are several 3rd-party options on the market.