What does pending mean on card?

It means that they haven't finished processing it yet.  It will go through (probably) but it hasn't yet.

Pending means "awaiting decision or settlement"......... you know you paid, it has been claimed and will go through, some banks are slow to move money, others it is instant.

There are many payment systems and a transaction is not instant. Instead, it is in pieces. In using the app, the merchant got authorization for £8.95. When the merchant runs their accounting, the actual charge is put in and could be 8.95 or more if you allowed it like a gratuity. After the merchant puts the final charge in his system, it passes to a clearing central and then to your bank who subtracts it from balance.

The money is spent and will equalize either overnight or in a few days depending upon the systems used. Don't spend the -£8.95. Your banking system may show AVAILABLE balance as around 60. 

Many teens wonder why everything is not instant. The reason is that it's cheaper to update systems in batches. 

It will go thru.