I was able to enter Course World yesterday evening, however earlier in the day it said the service was currently unavailable. Most likely that was because I tried going online before the game was out in Japan.
Being as the game is not officially released outside of Japan yet, it could just be that the servers for other regions are not 100% operational yet.
Also, I noticed there was a Day 1 update that prevented me from going online, and it didn't seem to be available yet, however an hour or two later I noticed that it said version 1.01, so it must have automatically downloaded the update.