他哥哥今年九岁。

Tā gēge jīnnián jiǔ suì.

His older brother is 9 years old this year.

这家公司每月九号发工资。

Zhè jiā gōngsī měi yuè jiǔ hào fā gōngzī.

This company pays salaries on the 9th of each month.

他不是八岁，也不是九岁，他十岁。

Tā bú shì bā suì, yě bú shì jiǔ suì, tā shí suì.

He is not 8 years old, neither 9. He is ten.