Is it possible to restrict access to the Moderation Center to only the Administrators?
If so, how? :D
Yes. It's simple. Just don't give any members moderation-level powers (making them a group moderator, making them a moderator on one or more boards, etc.)
If you're concerned about what's displayed there - keep in mind that viewing it as an admin will cause it to show you everything. SMF's permissions will restrict what users can see there (for example, the user will only see unapproved posts, topics and attachments from boards where they have permission to approve those items).