Your chess.com is less than your FIDE......... and you have been playing for 3 years.
is a USCF rating of 873 good for a 9 year old?
Honestly, if you even start USCF at the age of 9, you're probably going to be pretty good in the future. My uscf was 1640 when I was 9 btw not to brag.

no its not good. Thats the age of some of the youngest masters,even cutting that rating is half is still above 900. IT is probably ok though, you have plenty of time to improve.
I told na guys people wont understand. :C