The design of the OnePlus 9 has leaked, four months before its expected release in March 2021. The OnePlus 9 will have a 120 Hz and flat display, according to the same leak, along with a 5,000 mAh battery. A variant of the device has debuted on Geekbench too with a Snapdragon 875 and 8 GB of RAM.
https://www.notebookcheck.net/Probable-OnePlus-9-appears-on-Geekbench-with-a-Snapdragon-875-and-8-GB-of-RAM-as-pared-back-design-leaks.504318.0.html