...the next evening? Our wedding date is set for Aug 9th, but my fiancee and I were thinkig of a small (family and close friends only, 25 guests or less) wedding in the area we live in on the morning of the 8th (to have 08/08/08 as our anniversary and wedding day), and then a large reception at the hall on the 9th, since we already have it booked and paid for.
Most likely we will just get legally married on 08/08/08 and have the actual wedding and anniversary on the 9th.

I think that if people aren't invited to the ceremony (unless you would have two ceremonies?), some are less inclined to come to a separate reception because they missed the part that they are supposed to be celebrating with you. I could see how some people might take it the wrong way. But you know your crowd better than anyone!

Nah. That sounds fine. In fact, at most weddings, more people only attend the reception instead of the ceremony. People enjoy the party.