Although modern fast chargers can put out a range of voltages with a suitable communication chip, the older standard was limited to just 5V. For higher voltages like 9V and 12V you can use these little adapters that take the 5V in and boost it up to the desired voltage.
Note that these are probably only suited to about 500mA at 12V.
An interesting use for these could be for powering short sections of 12V LED tape from a USB power bank. For longer run time you could also power the tape from a 9V version at the expense of intensity. The lower voltage and current could allow you to run much longer strips.
The voltage selection is either hard wired in with two resistors forming a bridge, or on some it can be adjusted with a small knob. For the fixed voltage versions it is viable to modify the resistor values to get a custom voltage. The boost converter chip in this unit is looking for a feedback voltage of about 0.6V at the required output voltage.
You can buy these from many online sellers. Here's a link to a typical one on AliExpress (not a sponsor):-
https://www.aliexpress.com/item/1005006890061479.html
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