I have a 9 month old cat that I got a 5 months old from the breeder, Sundance was trained only to use a scratching post and he does, just as a precaution before I brought him home I covered the corners of the furniture with double sided stick tape, works great!

Declawing is a very painful traumatic experience, they are kept at the vets for at least 2 days in case any complications develop, I would never, never declaw. With training your kitty can learn what not to scratch, good luck.