You just need ONE member to have the account/buy the tickets - the other 8 (goes up to 9 as people have mentioned) do not have to be students/have a tdf account, etc.
However, I WOULD bring a print out of the confirmation with you when you pick up the tickets. It seems to vary by show and house what the policy is for pickup. Sometimes I've been asked for just the name - sometimes the confirmation. I haven't had anyone ask for ID yet but I heard Arcadia was doing that for some reason. (There's a thread here somewhere about that.)
Another tip is that they say pick up the tickets a half hour prior to curtain but you can always get them earlier in the day than that. I tend to pick mine up an hour or more before curtain (sometimes 2+) then go do other stuff and come back which saves a LOT of time waiting in lines.
2010: Next to Normal (May 25), Hair (Jun 9), American Idiot (Sep 10), Bloody Bloody Andrew Jackson (Sep 26), The Scottsboro Boys (Oct 17), Fela! (Nov 14), Next to Normal (Dec 30)
2011: That Championship Season (Feb 15), La Cage Aux Folles (Mar 16), The Book of Mormon (Mar 16), Anything Goes (Mar 30)