You have been with Kroger for over 8 years and you don't know the rules?
At my store, we turn in our vacation requests by Feb 1st. Then, your requests are entered into a grid by seniority. Holiday weeks are blocked out.
From there, each store might be different. Only one person can take a vacation each week in my department. Only one person in the entire store can take a vacation during the blocked out holiday weeks. That will be decided by who has the highest seniority.
In my store, NO one is allowed to take blocked weeks, but it depends on who your management team is, really.
Read your contract. If it says that vacations will be allowed 52 weeks out the year, then they have to allow them. They can limit the number of people that can go based on how it affects the particular department. For smaller departments like bakery, dairy, and frozen they might not allow anybody to go unless there's someone to take their place. On the front end they might allow two or more people to go because they can simply give those people's hours to the other remaining front end people.
you'd be hard pressed to get vacation time during christmas. they want you to be miserable and work through the holidays as much as possible, especially since they are extremely busy times. you could give it a shot, but don't get your hopes up.