I get the same message. I have 2 apple IDs to check, it let me check one but not the other. Then when I tried the first again out of curiosity, it wouldn't let me check that one either. Maybe their system is just bogged down at the moment.
Yep, just checked mine. Says delivery 09/19. Their servers are probably still getting hammered with inquiries, so it may be hit or miss today. Just check back a little later and I'm sure it'll come up for you.