To simplify the fraction \( \frac{9}{63} \), we can divide both the numerator and the denominator by their greatest common divisor (GCD).
The GCD of 9 and 63 is 9.
Now, we simplify:
\[ \frac{9 \div 9}{63 \div 9} = \frac{1}{7} \]
So, \( \frac{9}{63} \) in simplest form is \( \frac{1}{7} \).