However they present it, it's cynical in the extreme and completely against the spirit of recent legislative moves.
There are lots of business that I buy goods and services from who don't charge me an admin fee - why should airlines be different. I can understand if they are having to print something off for me (as is the case for theatre tickets often for example) but I check-in myself and print the boarding card myself. What are they doing for the £9?
I can understand the percentage for credit card usage but debit cards are a guaranteed payment.
It still may be better than the appalling FR (in this context) but it's really scummy business practice.