Last year, students across grades 6-9 were engaged in personal projects over the course of their summer break. All these projects have been collated on a website. You can go through pages of the website like "Outstanding Work" and "Other SLPPs". This would help you understand what kinds of projects have been done previously and might also give you some ideas that you could incorporate in the project you are planning to take up.
The following the link for the Summer Live Personal Project (SLPP) website:
Keep checking this page for updated list of resources