如图,在平面直角坐标系\(xOy\)中,椭圆\(E: \dfrac{{x}^{2}}{{a}^{2}}+ \dfrac{{y}^{2}}{{b}^{2}}=1\left(a > b > 0\right) \)的离心率为\(\dfrac{\sqrt{2}}{2}\),上顶点\(A\)到右焦点的距离为\(\sqrt{2}.\)过点\(D(0,m)(m\neq 0)\)作不垂直于\(x\)轴,\(y\)轴的直线\(l\)交椭圆\(E\)于\(P\),\(Q\)两点,\(C\)为线段\(PQ\)的中点,且\(AC⊥OC\).
\((1)\)求椭圆\(E\)的方程;
\((2)\)求实数\(m\)的取值范围;
\((3)\)延长\(AC\)交椭圆\(E\)于点\(B\),记\(\triangle AOB\)与\(\triangle AOC\)的面积分别为\(S_{1}\),\(S_{2}\),若\(\dfrac{{{S}_{1}}}{{{S}_{2}}}=\dfrac{8}{3}\),求直线\(l\)的芳程.