Can you write a quadratic equation with the solutions of 0 and 9

That is easy, lets get two factors with those solutions:

x (x - 9) = 0

that equation is solved if x = 0 because one factor is zero, and if x = 9 as well for the same reason (try it!), so the equation is:

x (x - 9) = 0

x^2 - 9x = 0