To find the $y$-intercept of the equation $x - y = -9$, set $x = 0$ because the $y$-intercept is the point where the line crosses the $y$-axis, and at this point, $x = 0$.

1. Substitute $x = 0$ into the equation:

   $0 - y = -9$

2. Simplify:

   $-y = -9$

3. Divide by $-1$ to solve for $y$:

   $y = 9$

So, the $y$-intercept is $(0, 9)$.

Would you like more details or have any questions?

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1. How would you find the $x$-intercept for $x - y = -9$?
2. What is the slope of the line represented by $x - y = -9$?
3. Can you rewrite $x - y = -9$ in slope-intercept form?
4. What would the graph of $x - y = -9$ look like?
5. How would you find the point where this line intersects another line?

Tip: Remember that to find the $y$-intercept, always set $x = 0$ in the equation.