What silly babies they all are! If there are just a couple of specific spots Kirin is scratching at, you could try spritzing those spots with a bit of Feliway, or - if you need something less expensive and/or he's just doing it at any old spot, you could try spritzing something citrus-scented on/around the walls. And maybe also try some spray-on catnip on the scratching post to entice him over to it more.

And then there's the squirt bottle method (works like a charm with bad behavior around here). Mix a little bit of vinegar in with some water and PHEW! If Kirin gets squirted with that a time or three, he might think twice about scrabbling his claws on the wall!

Goodness knows when my herd sees me reach for the bottle, they straighten up real quick. They've gotten so that they equate anything that squirts/sprays with the squirt bottle. So if I'm spraying around a bit of air freshener, kitties scatter and I get these big, "What I do!?" looks.