To solve \( 9^9 \cdot 9^{-6} \), we can use the property of exponents, which states that \( a^m \cdot a^n = a^{m+n} \).
Applying that property:
\[ 9^9 \cdot 9^{-6} = 9^{9 + (-6)} = 9^{9 - 6} = 9^3. \]
Now, we need to calculate \( 9^3 \):
\[ 9^3 = 9 \cdot 9 \cdot 9 = 81 \cdot 9 = 729. \]
Therefore, the numerical equivalent of \( 9^9 \cdot 9^{-6} \) is \(\boxed{729}\).