Part of your problem is probably because you’re trying to book 9. I’m sure there aren’t a lot of tables if any built into the reservation system. As you said, calling in should have more success.
You will be able to get something booked if you wait until you are onboard, but if you’re not early you will probably get less than ideal times.
If you would be more flexible and break the group into smaller ones you’d probably have more success now.