There are three amperage values.
Normal running, maximum, and starting.
If 9A is maximum, then starting is probably 25 or 30a and running about 3
or 4a. Maximum is also known as the stall amperage because it hits that
when the motor is so over worked from clogged bag and restricted ducts that
it is about to stall.
But, you see the problem with using it at 120v. If it is 30a starting at
240v, then it is 60a at 120v. You aren't going to get 60a over #12, and the
motor won't like starting at reduced amperage.
So, you can do it, but it is not a great idea.
My PS DC was advertised as having an 18a motor, but it shipped with a 16a
motor. When I complained, they didn't have the courtesy to answer. Good