I gave my male, neutered, a grass mat in his cage. He loved to dig out the litter from his litter pan, I thought this would help that. It did, he tore up the grass mat, and before he gets fed in the morning-OMG he goes crazy digging at it. He still digs the litter out, but only right after I change it and then what he digs out, I keep putting right back in the litter pan, after a couple days, he quits digging it out. Problem is, he likes to lay in it too. He's trying to make a clear space for him to lay down, he's crazy, but I love him!!!
Rabbits love, I mean love, to dig, chew and burrow. So this is normal. Maybe get a grass mat for him to take out his frustrations on for now, until you can futher figure out his likes and dislikes.
The scratching, I'm thinking you are describing as digging? Real fast w/ front feet?