He will reach the ground after 2.023 seconds.
To start, write a quadratic equation in vertex form with the given information about the vertex.
[tex]y=a(x-2.6)^2+9.2[/tex]
All that we need to solve for is a. Plug in the point (0, 9) and you will be able to solve for a and write the complete equation.
Now, just use the quadratic formula and you will get 2.023 seconds for when he hits the ground.