Information here:
https://www.radiomuseum.org/r/induct..._mark_211.html
may help. At any rate the output transistors look to be the same and it's unlikely that Bettor would reinvent the wheel for each model.....
The main rail voltage is 28V but it looks like the preamp supply is around 7-8V so your 9V should be fine.
What type of pickup cartridge does yours have- the information I found is for a model with a ceramic type but the preamp setup in yours looks a bit more complex?
A quick Google suggests that perhaps "ben" in this forum has at least had some incidental connection with one of these in a Spanish forum!