Note that Access is an Elective for this certification, which requires you
to be highly proficient in Word, Excel, and PowerPoint.
In addition, the Access skills required for this certification do not
include VBA coding.
In the terminology I use, a person with Office Specialist Certification
would be a power user, rather than a developer.
AFAIK, Microsoft currently offers no certification relevant to Access
development.
There are other groups (e.g. Brainbench) which do.
HTH
- Turtle