The query "how deep is the 9" seems ambiguous, but based on the search results, the closest relevant interpretation is likely related to extreme depths such as the "Challenger Deep" — the deepest known point in the Earth's seabed, which is part of the Mariana Trench in the Pacific Ocean. The Challenger Deep has a depth estimated around 10,920 to 10,935 meters (approximately 35,827 to 35,876 feet) below sea level, based on various scientific studies and sonar measurements conducted over decades.
If the intended question was about something else related to "9" such as the 9/11 memorial or a game season 9, please clarify for a more targeted answer.
