Yes, you can. But only if your trademark application is filed through Amazon’s IP Accelerator Program.
Normally, Amazon requires a registered trademark number (not just an application) to approve Brand Registry.
However, IP Accelerator is a fast-track program that connects sellers with Amazon-approved law firms. Once your application is filed through them, Amazon gives you early Brand Registry access, even before the trademark is officially registered.
This means you can start protecting your brand, use A+ Content, and access your brand analytics while your trademark is still under review.