Currently stripping popcorn ceiling on entire first floor, shoring and patching dry wall on all walls and ceiling, painting entire first floor, and replacing most fixtures and rugs. May not sound like much, but it's full time. First spruce up place has had in 21 years. Also replacing pads and rotors on car when I need to take a brake (intended) from the dust and endless sanding.
My sister's creosote build up in her exhaust pipe ignited one Thanksgiving. A fire of sticky tar, in a tube running through inaccessible walls and roof. That was interesting (ripped the pipe out quickly and it was contained). You may want to inspect before adding in a new exhaust, if you haven't yet.
Ashamed to say I never thought about it till you. Glad to say it's gonna be a spicier "BEE-haw!!!" from now on!
Sorry, no, I don't know how you can fix a 9 year old.