Would it be safe to use one USB 1U tile to power an USB hub and then from that several devices both directly and through USB to 9V adapters ? Typically for me that would be a quNexus through USB and a Koma Kommander and maybe one or two effect pedals through USB to 9V cables/adapters…
I’m powering the quNexus directly now and things work fine but I’d love being able to power a few other devices through an HUB if that wouldn’t make anything fry or get too hot/etc.
It really depends on the current draw, and also how much current the USB hub is able to provide on each of its output and how much it’s able to draw from the USB bus. If you have a TPS80 power supply then you have a maximum of 1.5 A of current and that includes any modules that draw directly from the 5 V bus on the power supply, a TPS30 will have 1 A max. Technically the USB spec allows for up to 0.5 A to be drawn from a powered port, so a USB hub will be designed to pull no more than that (and probably less) from the port it’s connected to, and then split that current amongst all the devices connected to it.
As kamil wrote, it depends on the current draw. But in general, if you want to power multiple (non-low-power) USB devices through a hub, it will require a hub that can draw power from an outlet - USB power to the hub will not be enough.