Canon Rumors confirmed the RF 200-800mm f/6.3-9 has a USM motor, and will be announced on November 2, 2023. The Ordinary Filmmaker believes the announcement will happen tomorrow just after midnight, but has not received confirmation as yet.
Canon Rumors also included a leaked image of the RF 200-800, though it is a pretty poor image. It does show that the lens does come with a hood and is definitely getting the white treatment. This looks like a pro level lens, and not some cheap entry level lens.
Canon RF 200-800mm Specifications
- Focal ratio range f/6.3-9
- USM motor
- Diffractive Optics
- White paint treatment
- Not weather sealed, but we're confused by this one
- $1,999 – $2,199, or €2,499
- November 2, 2023 announcement
- Protected by Japanese Patent 2022-0035144
Most canon lenses above $2000 are usually weather sealed, but they are also usually L series. The only non-weather sealed L-Sereis is the EF 400mm f/4 DO IS USM II at $6,899.

While not weather sealed, I would be surprised if it just leaks water. Most Canon lenses can take some moisture. If only Canon would provide an IP rating for their lenses.
The Canon RF 800mm f/11 works with Canon's RF extenders so it will likely work with the RF 200-800mm f/6.3-9. However, what range will we get with the extender installed. The RF 100-500 only delivers 300-500 with the extender installed. That results in a zoom factor of 600-1000.

Moreover, with a 2x extender, the 200-800 f/6.3-9 becomes a 400-1600 f/12.6-18; a 1.4 extender will effectively provide 280-1120 f/8.8-12.6.