9. Given the function
$$
f(x)=\left\{\begin{array}{ll}
3 x-1 & x \leqslant 1 ; \\
\frac{2 x+3}{x-1} & x>1
\end{array}\right.
$$

If the graph of the function $y=g(x)$ is symmetric to the graph of the function $y=f^{-1}(x+1)$ about the line $y=x$, then the value of $g(11)$ is