Hi Ben and Rick,
This course is SO well made and brilliantly structured/composed. My nephew is coming up to 10 years old and I think something targeted at his age group would be astounding. To be able to build fun and simple applications and games whilst learning code would really help to build confidence and encourage learning outside the classroom.
All the best
Ben
The educator in me things that this is a great idea.
Just be sure and price it reasonably, eh?
One of the biggest difficulties with this idea may be age restrictions with regards to online services. For example, Facebook, 13 years old. Most forum software suggests a similar age. Udemy stipulates that children under the age of 13 will not register, and those between 13 and 18 should be supervised. There wouldn’t be anything on Udemy to prevent a 13-18 year old purchasing other courses on their parents’ credit cards either! 
Additionally, children do require an additional level of protection in my opinion with regards to messaging and so forth, this forum software doesn’t currently support a method of preventing any form of direct messaging for example, this could make it more challenging to offer them a safe environment.
Children, some, not all, may also lack the patience to wait patiently for answers to their questions when things are quite going as they had hoped. They may also be a little more prone to kicking off in messages when they’ve not yet had a response. These situations could be potentially difficult to manage virtually as opposed to in a classroom environment.
Obviously, I am not trying to tar all children with the same brush here, but just pointing out a few things which could be potential challenges. I think, with the right environment, targetted age-related content, it would be a good idea.