Osaka Aquarium Kaiyukan Ticket

Hi - I am arriving in Japan on the 26th of May at Kansai international airport and am trying to think of the best value for money tickets before I get my JR pass. I am wanting to get a Osaka Aquarium Kaiyukan Ticket at the airport when I arrive, and use this to take the train to my hostel. However, since I arrive so late I am wondering if I will A) be able to even purchase it and B) am I able to use the vouchers/coupons it comes with that give discounts to the aquarium plus a variety of other places on another day? So if I arrive on Saturday, can I use the vouchers on Sunday?

Thanks - and sorry if that is confusing!

I think you mean the Osaka Unlimited Pass: http://www.pia-kansai.ne.jp/osp/en/index.php

You can purchase that at the airport. It comes with a transportation card. As soon as you use the transport card, a date will be stamped onto the back of it. Since you have to show the card to use the coupons that come with the packet, as long as you don't use the card until the day you wish to visit Kaiyukan, it will be alright. That is, if you get the one day pass. If you get the 2 day pass, then you have an extra day to use the coupons.

This is the ticket you mean. 4th one down on this page.
OSAKA Kaiyu Ticket is a one-day, unlimited travel pass for Osaka Municipal subways, New Tram, and buses throughout the Kansai district. It can be used as the admission ticket for Osaka Aquarium Kaiyukan.
http://www.osakacity.org/en/tour/tourTips.aspx