Answer:
 Standard form (x - 0)² = 4(-9) (y - 0).
Step-by-step explanation:
Given  :  parabola with a focus at (0, -9) and a directrix y = 9.
To find : Find the standard form of the equation .
Solution : We have given focus at (0, -9) and a directrix y = 9.
 Standard form of the equation:  (x - h)² = 4p (y - k).
 Where the focus is (h, k + p) and the directrix is y = k - p. 
Focus ( h , k+p ) = ( 0 , -9)  ;  
Here ,  h = 0 , 
k + p = -9 .
directrix y = 9.
 k - p = 9
k + p = -9 
___________    ( On adding )
2k = 0
k = 0.
Then  k - p = 9 
Plug k  = 0 
0 - p = 9
p = - 9.
Plug all values in standard form of parabola.
 (x - 0)² = 4(-9) (y - 0).
Therefore, Standard form (x - 0)² = 4(-9) (y - 0).