Admissibility in the classification depends on the Appendix 2 qualification, not on the state licence. Whether he may lawfully perform the work is a separate question the state decides, and the answer can be no.
Eligibility and practice permission are separate gates
The two are commonly conflated because for some professions the same document satisfies both. The classification asks whether the applicant holds the qualification the profession entry names and has prearranged professional employment with a United States employer. The state asks whether this person may practise within its borders, and it applies its own standards, examinations and processing times. An officer may well ask about licensure as part of assessing whether the position is genuine and whether the applicant can actually perform it, so being unlicensed and unable to explain the plan is a weakness even where it is not a legal bar. The sensible sequence is to have the licence application filed and its expected timing documented before travelling.
Hypothetical example: A Canadian biologist with a biology degree is offered a United States role analysing freshwater samples for a conservation laboratory. The initial review should place the profession entry beside the degree transcript and the signed duty schedule. Those records settle the qualification and the professional character of the job; a recruiter’s verbal assurance does not. The applicant should also identify the entity that pays and supervises the work before travel. If she instead proposes to provide the same services through a corporation she controls, the classification cannot be used for that arrangement.