How many drivers did not race in 2009?
SELECT count(DISTINCT driverId) FROM results WHERE raceId NOT IN( SELECT raceId FROM races WHERE YEAR != 2009 )
drivers not raced in a specific year refers to selecting drivers not associated with raceIds from that year; count of such drivers requires DISTINCT count on driverId; races not in 2009 involves selecting raceId from races where the year is not equal to 2009.