I have 4 different breed puppies right now,all around 9-10 months and I know what you mean about eating things including the furniture.What I find that works best is tired puppies and lots of toys.We go to our local petco clearance bin and the dollar store regularly and buy tons of toys that are just a couple of dollars some only last 15 mins. but for $1.00 it keeps something else safe and keeps them happy.I find cheap things to tire them out.My shiba Inu for instance loves to chase and catch bubbles with my Goddaughter and Granddaughter.All the puppies love to chase and jump after peacock feathers and I have a friend who's mom has peacocks and gives us the feathers off of the ground.The dog park,trips to the pets store,walks,runs anything to tire them out.When I have to leave I crate them but they love their crates and have holves or something to chew on or cuddle and are usually tired out,or I make up a Kong stuffed with goodies either frozen or not and they have that while I am out.It has gotten much better and I am told will continue too.Plus we went to basic obedience and plan to continue so that helps and continueing to work with them always helps.Pupies chew and I figure if they get something I left out I should have moved it but at the same time they learn.I hope some of these ideas help.
Laurie