Answer
$1$
Work Step by Step
Using $_nC_r=\dfrac{n!}{r!(n-r)!},$ the given expression, $
_{9}C_{0}
$ evaluates to
\begin{array}{l}\require{cancel}
=\dfrac{9!}{0!(9-0)!}
\\\\=
\dfrac{9!}{0!9!}
\\\\=
\dfrac{\cancel{9!}}{(1)(\cancel{9!})}
\\\\=
1
\end{array}