i was more concerned about our house burning down or our furnace blowing up going from 69 to 92.
6 years old.
well on the list of things I'm not qualified to comment on is: HVAC systems...but with that said
I think very little risk here
I assume the system is new in the last 25 years?
if so there are lots of saftey/shut off features that would prevent a fire/furnace explosion
also it just slowly tries to raise the heat, not like it turns some flame on to Ludacris flame levels to get to 92 in a few mins
cut the 6yr old some slack...it's a learning opportunity. Should go show them the big scary furnace and how it's dangerous and not to play with it (althought that can backfire too) and show them how to change the air filter (you do that every 3-6 months, right)