RenderMan for Blender includes two different denoisers, one that is suitable for interactive work, and the other is meant for final renders.  

Interactive Rendering

Batch Rendering

To denoise your final renders in RenderMan for Blender, follow these simple steps, and for more detailed information on using AOVs in Blender, here is the link!

1. Go to the View Layer Properties and click Switch to RenderMan Displays
   
   
   
   
   2.  In the RenderMan Display, select your beauty AOV and turn on Denoise
   
   
   
   
   3. Set any denoiser parameters and you're all good to go!
   Note : if you are rendering using Blender Batch, then you will need to turn off Use Blender Compositor.
   
   
   
   

Pixel Variance = 0.26
Max Samples = 64