ここの九kokonoつtsu９９つtsu
1.
The numerical representation of the quantity that comes after eight and before ten, often used to count objects or things.
2.
The age equivalent to eight years plus one, specifically referencing a child who is nine years old.
3.
A historical term used to denote a specific time of day, roughly referring to midnight or noon in modern timekeeping, associated with the hour marked as "nine."
Example:
太陽をまわる惑星は９つもあり、地球もその１つである。