Check student rating:

https://ratingsnw.com/ratings.html (all Chess Players in NW use this system)

https://new.uschess.org/civicrm/player-search (US Chess rating) 

View state qualified players:
https://ratingsnw.com/qualifiers.html (all WA scholastic K-6 chess players)

Tournament registration websites:

ChessReg: https://chessreg.com/

NW Chess: https://nwchess.com/OnlineRegistration/

US Chess membership: https://new.uschess.org/join-us-chess

Washington chess federation: https://www.wachess.com/

Chess Platforms: