Hello,
You need to config pool poweron first, then vm poweron.
xe pool-param-set uuid=XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX other-config:auto_poweron=true

xe vm-param-set uuid=AAAAAAAA-AAAA-AAAA-AAAA-AAAAAAAAAAAA other-config:auto_poweron=true