Which area served coed genders at Kaharoa school and had a Decile of 9?
CREATE TABLE "rotorua_district" (
  "name" text,
  "years" text,
  "gender" text,
  "area" text,
  "authority" text,
  "decile" text
);
SELECT "area" FROM "rotorua_district" WHERE "gender"='coed' AND "decile"='9' AND "name"='kaharoa school';