9.
已知曲线\(C\)的参数方程为\(\{\begin{matrix} x=-1+2\cos \theta \\ y=1+2\sin \theta \\\end{matrix}(\theta \)为参数\().\)以原点\(O\)为极点,\(x\)轴的非负半轴为极轴建立极坐标系.
\((\)Ⅰ\()\)求曲线\(C\)的极坐标方程;
\((\)Ⅱ\()\)若直线\(l\):\(\theta =\alpha \left( \alpha \in \left[ 0,\,\pi \right),\,\rho \in R \right)\)与曲线\(C\)相交于\(A\)、\(B\)两点,设线段\(AB\)的中点为\(M\),求\(\left| OM \right|\)的最大值.