I'm very unsure about my plan for the summer as a freshman going in to 10th...

Yes teaching dance lessons and earning certifications are a great start for building leadership skills and expanding upon your passions!

I would suggest taking online courses over the summer through websites similar to Coursera over your topics/subjects of focus for the research project that you would like to conduct. As a freshman I doubt you have the basic knowledge required for conducting research work, so it's a great idea to familiarize yourself with those topics to fabricate a specific research question to develop your research over. Consider taking AP Seminar and AP Research in order to develop these skills as well as AP courses related to these topics. For now I think understanding and familiarizing yourself with the basics of research is better than going directly in without any former knowledge. After you have a clear idea of your topics of focus and the basics of conducting research, cold email professors and researchers with your resume for collaborating over a research study during the summer after your junior (it might take awhile to have a professor accept you, so start emailing the summer of your sophmore year), so that you can maybe conduct your own research project independently later on.

In addition to self studying AP Courses and taking online courses over the summer, you can start volunteering and shadowing professionals in places related to your interests like nursing homes or animal shelters, etc. This can help build great experience in leadership which would also helping you discover your passions. Since you are still a freshman, I suggest taking it slow and exploring different fields, building up knowledge and leadership experience. Hope this helps! Good luck :))