The number \(-8 \cdot 9\) can be calculated as follows:
\[ -8 \cdot 9 = -72 \]
A rational number is defined as any number that can be expressed as a fraction \(\frac{a}{b}\), where \(a\) and \(b\) are integers and \(b\) is not zero. Since \(-72\) can be expressed as \(\frac{-72}{1}\), it is a rational number.
Therefore, \(-8 \cdot 9\) is a rational number.