Can I install iOS 8.1.2 (12B440) on iPad Air 2 ?

We run a custom app on our organization and it works only with iOS 8.1.2 (12B440). If we purchase new iPads like the iPad Air 2 which comes with iOS 9 is it possible to downgrade them to iOS 8 in the version we need ? Also the new iPad Pro works with iOS 8 ?

Thank you in advance.