I have a customer requirement, that he wants to access a particular url which is in a blocked category. And also that url should be accessed by him only and all other urls in that blocked category should be failed for him.
For all remaining users, entire list in the blocked category should not be accessed.
Create a custom category for this one url in Web Security Manager>Custom URL Categories
Then create an access policy above the policy that does the blocking. Set the identity to be the user in question, set the URL filtering to allow this new category, and leave the rest to come from the global, or set them to what they need to be if the blocking policy isn't global.. (that way this user gets blocked for all of the other stuff he should be blocked by).