Which version of Adobe Acrobat (Acrobat 9 or Acrobat X) goes in certification track when you choose Adobe Certified Experts (ACE) on CS5 (CS5 goes with Adobe Acrobat 9.3 but there is not exam from Acrobat 9.3)?
On the "Get Certified" web page http://www.adobe.com/support/certification/ace_certify.html it states:
To become certified as an Adobe Certified Expert (ACE) Master, you must pass the current exam for each of the products in the suite. All exams must be for the same version of the Creative Suite.
As both Acrobat 9 & X are available to take I would recommend taking the most current exam (X) because is you take 9 you'll have to recert to X within 6 months.