CREATE TABLE table_77533 ("Date" TEXT, "Visitor" TEXT, "Score" TEXT, "Home" TEXT, "Decision" TEXT, "Attendance" FLOAT, "Record" TEXT)

What was the date of the game when the Canadiens had a record of 31 19 9?
SELECT "Date" FROM table_77533 WHERE "Record" = '31–19–9'
SELECT "Date" FROM "table_77533" WHERE "Record" = '31–19–9'