The question "how long has it been since 9" is ambiguous without context. It could refer to a number of things such as a specific event at 9 o'clock, the number 9 as a symbolic or biblical reference, or a date like September 9 or a year ending in 9. Could you please clarify what "9" refers to in this context? Is it a time of day, a date, a symbolic concept, or something else? This will help provide an accurate answer.