general_fact: 9000 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 9000 is the index of a triangular number containing only 3 different digits.
trivia: 9000 is an uninteresting number.
historical_date: August 21st is the day in 1968 that James Anderson, Jr. posthumously receives the first Medal of Honor to be awarded to an African American U.S. Marine.