How much time does it take for the approval of CBD oil merchant account?

The cleaner the profile the shorter the time required.
In most cases if the merchant has all the required documents and the website full fills the processors requirements then the approvals can be as quick as 3-4 business days.
If the profile is complex and applications are getting rejected then the other processor will take similar time.
In general a weeks time should be enough to get approved if all goes well.