Hello Olivier,
Do you know where any of these shells came from?  That would be a big help.
I can help you with a few of them anyway.  Here are my best guesses:

#1  Looks like a subadult Melongena, and the operc also looks like
Melongenidae.  Not sure what species.  Perhaps Melongena patula??

#2  Looks like a small Hyotissa hyotis L.

#3  This is a species of Arca, but can't venture a guess without seeing the
rest of the shell.

#4  Anadara sp.  Not Anadara granosa.

#5  Looks like Semicassis diuturna  Iredale

#6  Semicassis persimilis  Kira  (often considered a subspecies or form of
Semicassis bisulcata)

#7  ? not familiar with the species kobelti.

#8  Hecuba scortum L. (family Donacidae)

#9  not Latiaxis nakayasui.  Probably L. spinosus.