Evaluate the following integral by interpreting it as an area:

${\displaystyle \underset{-3}{\overset{0}{}}}(1\sqrt[\phantom{2}]{9-x^2})dx$

$\frac{9x}{4}$

$\frac{129}{4}$

$\frac{9-12}{4}$

$\frac{69}{2}$

$\frac{9}{2}$

$\frac{9x-6}{2}$