There are 400+ teams attending and 200-250 college coaches expected. I don't think it's a waste of money at all, if your players do their due diligence and get their letters/emails out. We have had several players recruited and verballed as a result of this showcase in the past.
Being on the four main fields at WWOS is a pretty big deal. That's where the majority of the coaches hang out. We have been off-site in the past and have not seen many coaches. But I know they do come if they're looking at specific players.
Unfortunately this concept is lost on most people. Your players did not get recruited because of D9 attendance numbers. They got recruited because they worked the process. The number of coaches and teams attending is a moot point. What matters is if the coaches you have contacted are attending.