When was the winning score −9 (72-68-64-67=271)?
CREATE TABLE "champions_tour_wins_9" (
  "date" text,
  "tournament" text,
  "winning_score" text,
  "margin_of_victory" text,
  "runner_s_up" text
);
SELECT "date" FROM "champions_tour_wins_9" WHERE "winning_score"='−9 (72-68-64-67=271)';