You can ride a bike, but the rotation is too intense, you don't want it. Swimming is the most recommended.

Adult scoliosis is mainly maintained. Try to avoid load, distortion, vibration, etc. For the spine, especially sit-ups. But we should also pay attention to exercise the back muscles to provide support for the spine. Of course, everyone is different. If you can consult a doctor, it is best to tailor the exercise program.