9950 would be a rather IMPRESSIVE score - if it were actually possible.
Seeing as how you get 9000 points for solving all 5 equations (AND highlighting AND submitting your answers) in 100 seconds
For each second under 100 you earn an additional 10 points.
Therefore - YuYingjun would of solved, highlighted, AND submitted the answers to 5 equations in FIVE seconds. My guess is that's why s/he included the "hahahaha" in the original post.
A much more realistic top score is 9600 (3 to 5 seconds to solve, 2 to 3 seconds to highlight/find, and .5 seconds to submit - per equation)
Best I've ever done is 48 seconds (9520). I think I've seen 9560 once.