The main idea in the 9th amendment is that certain rights are to be protected from the government interfering with them, such as, people having freedom of speech of religion and others
Recording artist that don’t follow their labels rules
It was successful because when all blacks boycotted the buses, that takes a huge chunk of change out of the cities bus money which was a staple in how the city lived. Don't quote me on that though. Sorry it took someone 2 hours to respond to your question. Hope I helped :D