Hi Megan,
"Kids astronomy" is, from my experience, is school based on the most part. Either the school organises an excursion to an observatory, or an Astro Night is organised on site where other amateur astronomers bring their scopes.
We have a young fellow about your son's age come with his old man to the star parties we hold at Katoomba, 2 hours west of Sydney. The two of them have a scope each, the youngster with an 8" dob all of his own!
We love having him there. He isn't shy about being forward, and his enthusiasm is pulpable ALL night. He's become a part of the furniture really.
We've also had upto 5 kids attend our star parties with their folks.
We do our best to accomodate them and share our passion for this hobby with them. They are in many instances more than capable of grasping what can be very abstract physics principles better than most adults because of their fresh relationship with school science.
I held a star party at my wife's preschool a couple of years ago. I'm not kidding when I say that the 4 year olds had a better grasp of astronomy than MOST of the parents.
I'd encourage you to take you son to a star party, held by an astro club or by other IIS members, whether you have a scope or not. You'll both gain a lot from the experience, and be able to make valuble contacts. You might also be able to organise an astro night at your son's school with these contacts,

. Some clubs even have scopes that you can borrow. And folks at astro clubs and star parties on the most part are only too happy to welcome "fresh blood"

.
If you've got binoculars, take them along too. These are magnificent astronomical instruments (I always have them with me, at home or at a dark site).
Mental.