9.(2023•厦门模拟)圆OOO为锐角ΔABC\Delta ABCΔABC的外接圆,AC=2AB=2AC=2AB=2AC=2AB=2,点PPP在圆OOO上,则BP→⋅AO→\overrightarrow{BP}\cdot \overrightarrow{AO}BP⋅AO的取值范围为((( )))