Hi there and welcome to the community,
1) if you mean can you passthrough a USB device from the host to a VM then yes you can- Edit the settings of your VM to add a USB Controller first of all, then hook up your USB device to your host, then back in the VM settings you can add a USB Device which will allow you to select any USB devices connected to your host. This will of course however effectively tie that particular VM to that particular host, you won't be able to vMotion it to another host for example, or DRS will not be able to move the VM to balance the load (If you have DRS enabled)
2) vSphere does have APIs that allow backups but I believe these may not be publicly accessible and will be dependent on the vSphere license level (these are not available in the ESXi free hypervisor I understand). There are various workarounds you can use to create 'backups' of your VMs with PowerCLI however using the built-in functionality of vSphere, like this example from Simon Long which essentially creates a snapshot of your VM, clones it. You could also export the VM to OVF/OVA as another form of backup, depends on your requirements. There are also many choices of backup software available which have scripting functionality, Veeam being one of the more prominent, but again this functionality is only available with certain license levels of the software, again depends on your requirements, and budget!
Hope this helps and good luck,
vM
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VCAP-DCD / VCAP-DCA / VCP-CLOUD / VCP-DT / VCP5 / VCP4
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