I would work a ton on crate games. Teach your dog to drive into his crate and stay in there with the door open. Free hape this so it's a really fun game. Feed him in his crate.
Also start giving your dog a really good bone, or stuffed kong when you put him in his crate. Let him eat it for a short time while you are nearby. Then open the crate, remove the bone, and let him exit the crate. Repeat. This should teach him that he gets great things when in his crate, he doesn't get them when out of it. If he does really good with you nearby, start being in a different room of the house. Remember to come back and take away the bones before he's finished.
Also remember to completely ignore the whining. Don't even tell your dog to be quiet, or reassure him, as any attention could reward the whining. Wait it out. Only come back when he is quiet.
Some people have good luck with putting a blanket over the crate when the dog is whining. So you leave, come back and reward if he's quiet, but if he cries have someone put a blanket over it. As SOON as your dog is quiet, come back and lift up the blanket. Repeat. If you try this, remember to take away the blanket as soon as your dog is quiet. If you wait and always have the blanket covering it is no longer a training tool but is simply managing it.
I would use the crate whenever you leave your dog alone for right now. 9 months is a teenager and even if he's never destroyed something, he is at the age where he could easily be tempted.