CBD oil for dogs?

My husband and I adopted a rescue in April of this year. When we got him he was in really bad shape and not trained at all, he was very neglected and possibly abused. He still has some triggers like loud noises or sudden movements, but is doing really well overall now. It does seem like he still gets really nervous or anxious at times though, and will shake and constantly try to lick us as a result. My husband wants to try CBD oil and thinks that may help calm him down when this happens. Have any of you tried it or heard anything (good or bad) about it?