If a gulet has 9 cabins that means she can accomodate 18 person. The gulet can cruise with 18 person onboard in Turkish waters but can only leave Turkish waters with max. 12 person to foreign waters (same vice verse). But if you plan to cruise in Greek waters only and not plan to visit the Turkish coast, than your group can be 18 person. Again you can only be max. 12 person onboard to enter Turkey with a gulet (the rest can take the ferryboat!).