Is there a way to make a 2009 MacBook (A1342) boot from USB? I have a 2009 MacBook which I'm trying to factory reset/re-install. I have a USB bootdisk but sadly holding option to boot from USB doesn't work - I don't believe these models support it (A1342). It is definitely Intel (MacBook7,1, boot rom version MB71.0039.B0B). The Mac currently has Snow Leopard (OS X 10.6.8) installed.
Is there a way to load up and use the USB drive in an alternative manner? For instance from within singe user mode, or using a third party DVD bootdisk that will then, in effect, retro-fit the USB boot?
Or alternatively, is it possible to partition the main drive to create a recovery drive in some way?
Any Intel Mac should be able to boot from USB. So the possibilities are:

that this particular Mac can't boot at all
that the USB disk is not configured correctly.
that the USB port is damaged.

Make sure that the USB drive uses the GUID partition map (not Apple Partition Map, nor Master Boot Record).
Make sure the OS on the boot disk is an OS that supports that hardware: - macOS 10.6.1 (Snow Leopard) to 10.13.6 (High Sierra).