If you want to upload to YouTube or Facebook doesn't matter what rank you can upload. If you trying to upload to leaderboards you need to have the U rank.
Only PS3 players can upload directly to youtube. To upload to facebook, you go to options > online, where it will give you the option to connect a facebook account to DOA5U. Once you do that, whenever you go on spectator mode and select a video, an option will be there saying "Share on Facebook."
If you trying to upload to leaderboards you need to have the U rank.