What is the y-intercept (b) of a line that is parallel to $\displaystyle{y}=-\frac{{1}}{{3}}{x}+{6}\usepackage{cmbright}\Huge\$ and contains the point $\displaystyle{\left({9},-{7}\right)}\usepackage{cmbright}\Huge\$ ?

The y-intercept $\displaystyle{b}=\usepackage{cmbright}\Huge\$ _____.