hi,
if you'll buy your flight 9 days before it isn't a problem (except at Easter), you pay it, get your ticket and it's o.k.
But you have to bear in mind that the office of La Costena only is opened until 5.30pm (I don't know when your flight from the States arrives)!
Sending your credit card info per e-mail isn't a good idea - the only thing is to tell them the infos with a telefone call.

arambigua