The two points given are \((-9, 4)\) and \((-9, 2)\). Since both points have the same x-coordinate (-9), this indicates that the line is vertical.
The equation of a vertical line that goes through a specific x-coordinate is written as:
\[ x = a \]
where \(a\) is the x-coordinate of the points through which the line passes. Thus, for the points provided, the equation of the line is:
\[ x = -9 \]
So the correct choice is:
x = -9