Good luck with that one.
It has nothing to do with his age, but with the fact that he's a shredder.
I think, and this is just based on my own experience with Jazzy and Keoki,
a shredder is a shredder.
Jazzy has had the same blanket and dog pillow in her crate for a very long time. She has never shredded a blanket of any kind, not even when she was a puppy.
Keoki is 8 mos old. I have spent more money on bedding for him than I care to calculate.
He does okay now with his "night time bed", but I go through a ridiculous ritual to make sure he's asleep at night before I go to bed. {I give him tiny treats through the door of the crate, then quietly tell him "go to bed" over and over until he finally curls up and goes to sleep. I stay for several minutes until I hear his breathing change, then sneak out of the room}. As soon as I hear him move in his crate in the morning, I get up and take him out, so I don't give him time to start tearing it up. And the little **** gets up between 5 and 6 every day, so there's no more sleeping in for me!
Sometimes, during the days at home, he will run into his crate and pull his bedding out to play with. I have to be on top of that, grab the stuff back and tell him "NO". The other day I'd closed his crate, so he went in to Jazzy's crate, pulled her good pillow out and did get a small hole in that before I caught him. SUCH a brat. Interesting, he never even attempts to chew the big pillow that I got for Gypsy, which he also sleeps on during the day.
When I have to leave him during the day, I take the good bedding out of the crate and give him paper towels to lay on. It doesn't matter how long I'm gone, when I get back there's not much left but fluff.
Someone at a recent show told me to get "Egyptian bath rugs", which she had simply gotten at Big Lots. Said her shredders couldn't shred them. Unfortunately, the Big Lots here in town closed recently and I haven't gotten around to looking elsewhere {don't want to spend a lot, just in case….} so I can't personally vouch for them. She is someone whose info I believe I can rely on, though.
Anyway, good luck on that quest. I sure have no real solution yet, and think I may never!