Each spin is independent with outcomes $\{7, 8, 9\}$, each equally likely with probability $\frac{1}{3}$.

$P(\text{first spin} = 9) = \frac{1}{3}$

$P(\text{second spin} = 9) = \frac{1}{3}$

$P(99) = \frac{1}{3} \times \frac{1}{3} = \frac{1}{9}$