Blackbird with damaged wing feathers - what should we do?

Hello, I am new to this forum and I would be very grateful for any help you can give.

One of our cats caught a male blackbird and brought him into the house alive. My husband chased her outside where she dropped the bird and then sat beside him. The blackbird lay in shock, my daughter wept, we didn't know what to do. The blackbird suddenly sprinted off and the cat went after him. We panicked, I grabbed the cat and locked her in the house.

The blackbird seemed OK but although he could run, he couldn't fly. A couple of his wing feathers were pulled out by the cat. A couple of drops of blood fell on the kitchen floor when she brought him in, but these seem to be from the wing feathers, nowhere else.

We couldn't bear to just leave him to the cat so have put him in a box in a dark, quiet room.

Now I read that it takes 12 months for feathers to regrow. It seems to me it would be very cruel to try and keep him that long. Could I release him in the nature reserve near here? There are no foxes, though perhaps other predators.

I don't live in the UK and there is no wildlife rescue centre near me. I plan to ring the national one on Monday but if anyone has any suggestions about what to do in the mean time I'd be so grateful.

Have we done the wrong thing?

Thank you in advance.