Thanks Chris. That is good to know. I just tried it and you are correct - it now stays in "fixed" or "style" mode when I shut down and power up again. ...
Thanks for your quick feedback, Brian. I'm glad that I was able to help you with this question!
... I must say that so much of this stuff seems to be discovered by happenstance as opposed to being able to consult the owners' and reference manuals, both of which I find to be not terribly well written overall. ...
I recommend that you always open
both manuals on your computer at the same time and use the Search function of your PDF reader program/app (usually "Ctrl + F") to quickly find all relevant text passages for a specific search term in both manuals. (I always work like this myself.

)
It is usually good to open the CVP-809
Data List on the computer at the same time. There you will find important information about every single parameter of the CVP-809, e.g. in the already mentioned section "Parameter Chart". (Altogether there are many hundreds of parameters, but here you can quickly find what you are looking for using the mentioned search function. For example, today I first clicked on the "Parameter List" section in the table of contents for you in the CVP-809 Data List and then looked up with the search function "Stop ACMP" wanted.)
I was shocked to find only 11 preloaded songs in the playlist on the CVP 809 - As I recall the old MUSIC FINDER (which seems to have been abandoned by Yamaha) had over 50 preloaded songs. What is the simplest way to get more songs into the playlist? Perhaps there is a flash drive I can purchase with more preloaded songs? ...
Even with earlier models that still work with Music Finder, only a few sample records were included ex works. The so-called "Music Finder Standard Library" (which then contains around 1000 ... 2000 records depending on the model) always had to be downloaded and installed separately.
Please download the "Bonus Playlist for CVP-809 / 809GP" from the CVP-809 download page, unzip the zip file on your computer and copy the contained folder "CVP-809 Playlist" into the root directory of a USB stick (NOT in a FOLDER) on the stick!). This is also described in the "ReadMe.txt" file, which is contained in the downloaded zip file.
>>>
https://uk.yamaha.com/en/products/musical_instruments/pianos/clavinova/cvp-809/downloads.html#product-tabsThis Playlist package contains
1236 (!) Registration Bank files (.rgt) in five category folders. In each of these category folders you will find one Playlist file (.tsv) with which you can load the individual Songs (Registration Banks) contained in the folder from a
Playlist. (Of course you can also load the included Registrations
directly (without using the Playlist function) if you want.

)
... When I call up a style with the OTS link selected and look at the home screen, the portion of the screen labeled "LEFT" is virtually always greyed out (inactive?) whereas depending on the OTS assignments, "main" and "layer" are sometimes both yellow or just one of them is yellow. Yesterday I started touching the "LEFT" rectangle while playing and notice that when I strike a chord I can get additional rich accompaniments layered on top of the style that is already being played.
... I thought "Left" was only used when you are paying the piano without a style and you want to divide up the keyboard with a split point into a right (Main + Layer) and left. ...
Yes, this is the same on all PSR-S, SX, Tyros and CVP models and of course on Genos. You can switch each Keyboard Part on or off separately (on CVP-809 the Parts "Left", "Main" and "Layer"). The current state can be saved in Registrations or in OTS. (If you want to change the OTS of a
Preset Style you have to save the Style as a User Style because Preset contents cannot be overwritten.)
With the OTS of the Preset Styles, a
Left Voice setting is called up, but usually the Left Part is initially
deactivated. This is probably also due to the fact that when using the "AI Fingered" Chord Fingering setting, certain "chords" could be used, which would then sound "wrong" with the Left Voice activated.
Of course, you can switch
on the Left Voice at any time if you want. You could also move the left Split Point further to the right if necessary. Thenc you can play the Left Part in the keyboard area between the Style Control area and the main / layer area (i.e. no longer at the same time as the chords for Style Control).
I recommend saving all changes in
Registrations, i.e. NOT changing the OTS. Many settings (e.g. Split Points / Fingering) cannot be saved in the OTS. In Registrations, however, (almost)
everything can be saved.

Hope this helps!
Best regards,
Chris