$f\left(x\right)=a{x}^2+4x+c$

In the given quadratic function, $a$ and $c$ are constants. The graph of $y=f\left(x\right)$ in the xy-plane is a parabola that opens upward and has a vertex at the point $\left(h,k\right)$, where $h$ and $k$ are constants. If $k<0$ and $f\left(-9\right)=f\left(3\right)$, which of the following must be true?

1. $c<0$
2. $a\ge 1$