若\( f\left(x\right)=\{\begin{array}{cc}{\mathrm{l}\mathrm{o}\mathrm{g}}_{\frac{1}{3}}x   x\left(x＞0\right)              & \\ {3}^{x}+1\left(x\le 0\right)                  & \end{array}​\)则f[f(9)]=______.