1) Hour of Code and Blockly, as well as some Blockly Games, age 5-7
2) Khan Academy JavaScript and processing.js at age 7.
He's pretty awesome at JavaScript now. The programming courses on Khan Academy are great. I will mention your child needs to be ready for it. At that age, a few months one way or the other is huge, as is having the mechanics of typing and mousing.
Next step from there is the book "Code: The Hidden Language of Computer Hardware and Software (Developer Best Practices) " and Nandgame, as well as Micro:bit.
I recommend against Scratch. It's a rabbithole that goes in the wrong direction. You get stuck in a local minimum, where it's really hard to move onto real programming, and within Scratch, there are a lot of local minima (move to random position).