In a traffic stop where a k9 is used can you be charged with anything not related to drugs?

Recently I was stopped twice while driving down i95 through south carolina, during the first stop the officers claimed we were speeding and never wrote us a ticket, basically they ran our information and gave us a hard time and suggested getting a k9 to the scene. They eventually let us go without the k9 ever coming, we jump back on the road and less than 20 minutes later we're pulled over again and this time the officer has a K9. He claimed we were swerving over the white line this time. He requested our information and then said he wanted to K9 to walk around the vehicle. He claims the k9 reacted to the smell of drugs and that this then gives him the right to forcefully search out vehicle. No drugs were found, but he did find documentation containing personal information of people who were not present in the car. I was arrested for possession of that information. They let my friend go.