Would a compressor with 9 fad work I understand it's lowYou have indicated blasting "under a car"
So I can presume large areas and possibly a pressure pot.
In this case like my suggestion of a tandem compressor above then it's 18 FAD minimum you want. Anything less you'll have to stop and start all the time and it will be a painful process.
Good used is what you want - if in England you should be able to find a used tandem compressor for around your £400 budget.