Question 910749
It's already in vertex form although it's disguised.
{{{y=-(x-0)^2+9}}}
The vertex is ({{{0}}},{{{9}}}).
The axis of symmetry is {{{x=0}}}.
It opens downwards since the coefficient of the quadratic term is negative.
The domain is all real numbers. 
The maximum value occurs at the vertex so the range is ({{{-infinity}}},{{{9}}}).
{{{graph(300,300,-10,10,-10,10,-x^2+9)}}}