So I have an almost 8 months puppy. He is closest to my brother and I, and we spent a lot of time together this summer. But I left for college Friday night and my brother, who still lives at home, started school last week. And my mom just called me and told me that starting Sunday he has been ripping up the plants in our dining room while no one's home, which he had never done before. And the plants are actually in a huge pot that's pretty high up, so I don't even know how he did it. And today, my mom said that when she got home, he had dug half the soil out from the pot and there are pieces of the plants EVERYWHERE around the house! So I'm actually starting to get worried since he has never ever done anything like that before. Do you guys have any ideas? Could he be developing separation anxiety? But my brother still lives at home though. Any help would be greatly appreciated!

He may have been closer to your brother (as you think) but actually misses you so he is acting out. YOu have to leave something back at home, like a sweater you don't wear anymore. Anything with your scent on it and I am sure this problem will not occur again. He needs something with your scent, preferrable from both of you in some part of the house. He is getting too old to do this so someone has to take charge and break him of bad habits.

Yes it could be separation anxiety. You can help him with behavior modification or it WILL get worse. Call your vet to set up an appointment for consultation on a program.

For an indepth look at this problem see Companion Animal Behavior Program it has some programs using behavior and medication therapies as well as LOTS of links in laymen terms.

However, he could also be bored. The problem is every dog should be crated. But if it IS true S.A. the dog shouldn't be crated. So a vet visit or self education would help you decide.
Good Luck