I recommend you pick a topic that interests you and is relevant to you and your peers. Given that you state you are in 9th grade this could be around social media. Is there too much of it? What do you think about the privacy protection and age restrictions on facebook? Is it a stigma not to be on facebook or twitter? How important is social media in your life? What would your life be like without it? Does it impact on your social skills and life skills?Alternatively you could pick a school based topic such as the advantages and disadvantages of wearing school uniform or safety in schools. You could also reflect on the recent history of school massacres and debate the psychological impact on students. There are many facts readily available on each of these topics. Have a look at some great debates to get you started, the link below will give you some information about a political debate over slavery. Enjoy researching and remember, pick a topic that interests you.
This semester we debated
Is assassination murder?
Is welfare helpful or hurtful?
Should local law enforcement be taxed with policing illegal immigration?
Should the death penalty be illegal?
Is Civil Disobedience a lawful form of free speech?