You might check out a couple apps made for this. One of the mods tangled with accidentally reformatting a data drive with OS9. No one app seemed to get everything but he had good success getting complete recoveries using 2 different ones:
http://www.r-tt.com/data_recovery_macintosh/
and
www.r-studio.com//
Not sure which of them allow you to test it before purchase. But worth it to look them both over.
molṑn labe'
"I am a mortal enemy to arbitrary government and unlimited power. I am naturally very jealous for the rights and liberties of my country, and the least encroachment of those invaluable privileges is apt to make my blood boil."
--Ben Franklin