Answer
$1$
Work Step by Step
RECALL:
$y=a^b \longleftrightarrow \log_a{y}=b$
Let $y=\log_9{9}$.
Using the definition above gives:
\begin{align*}
9^y&=9\\
9^y&=9^1
\end{align*}
Use the rule $a^m=b^n \longrightarrow m=n$ to obtain:
$9^y=9^1\longrightarrow y=1$
Thus, $y=\log_9{9}=1$.