My kids are hooked on Minecraft, have dabbled with different types of free animation creation websites and my 9-year old son has also enjoyed using Alice and GameMaker. All of these wonderful resources gives people a view into computer programming while also being creative and fun.
What if you want to actually teach students/children how to code? You could jump straight into a 500+ page textbook and introduce how to code in a development environment. This might be appropriate in some senior years high school subjects. I’d like my 9 year old son to start programming but I also know if it looks too big of a task and if it’s boring he won’t bother continuing with it.