The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 1.7321i\\[1 em]x_2 &= -1.7321i\\[1 em]x_3 &= -0.5+1.6583i\\[1 em]x_4 &= -0.5-1.6583i \end{aligned} $$Polynomial $ x^4+x^3+6x^2+3x+9 $ has no rational roots that can be found using Rational Root Test, so the roots were found using quartic formulas.