Yes, you can drink water at whatever temperature that is comfortable for you. Temperature does not alter the composition or nutritional value of water.
Tip: Drinking cold water for weight loss
Drinking cold water will help you to burn a few extra calories, so if you are doing Clean 9 for weight loss, you can enjoy a tiny advantage by drinking your water cold, health permitting.
However, drinking iced water can be counterproductive in cold weather and may lower your body temperature unhealthily. Please exercise common sense whenever trying to lose weight by any means.