How much better is JHU CTY online math vs. Khan Academy? This would be for grade 7, pre-algebra.

Right now my 8 yr old 3rd grader is doing 7th grade math on Khan Academy during class. The district is giving him a JHU CTY placement test. If he places in the 7th grade level they will provide JHU CTY math for him in his class. However, if he places at 6th grade or lower then we are back to square one. Maybe continue with Khan Academy, maybe join the gifted 5-6 class who is using a 6th grade curriculum. Even with Khan, he still has some access to his teacher and I can also mentor him at home.

(P.S. I know there are tons of other options like AOPS etc, but let's stick with just JHU CTY vs. Khan, as that is what our district uses. I don't want to provide his math education from home, as I have been doing for the last three years)