Now that you are asking a question rather than just making a statment for us to figure out.
NO. Bumpstops would not help. You have a problem with your rebound damping. You need more of it. I would recommend trying new shocks or better yet better shocks. How old are your 9000's? I don't personally like the rancho shocks but won't hate on them in your application usless you tell us more about your setup. Rear springs, shocks, tires, air pressures and what you are doing that causes the suspension to do what you say it is doing. Help us help you.