I highly suggest physical devices over any other approach. Buy an RPi or an Arduino, and make cool stuff with it. Let your kid watch and help. Then teach them

I highly suggest physical devices over any other approach. Buy an RPi or an Arduino, and make cool stuff with it. Let your kid watch and help. Then teach them basic Python and let them write parts of functions/scripts with MicroPython. That's how they get started. I saw a boring, trivial Hello world Press any key to continue... It did not spark any interest in me. Programming was a mundane experience until math and programming were linked later. I was much more excited when I learned HTML at the age of 13/14. The fact that I could change text in a real web page on a browser was mind-blowing. That's why I do microcontrollers and suggest them always. The fact that you can change stuff in the physical, real world by editing a text file - is so tremendously powerfull for a beginner! Get some LEDs, a display, a servo motor, and so on, and let them watch and help. Then let him alter the sourve file to change light blinking patterns and such.