Yeah, 9v at the very least, but 15V would be a useful option too.

I’m also just now realising USB-PD doesn’t spec for 12V which feels like an odd omission

Edit:

From the article:

Sure, it wouldn’t be much harder to add support the other voltages offered by USB-C Power Delivery, but how often have you really needed 20 volts on a breadboard? Why add extra components and complication for a feature most people would never use?

My friend, you write for hackaday, this is a weird take