I don't see any reason why not provided
1) The welding test was performed within the variable ranges of an ASME WPS
2) The test welds were visually inspected and acceptable within the requirements of ASME Sec IX
3) the applicable mechanical tests or Radiography were performed in accordance with the requirements of ASME Sec IX a
4) and all of that was documented and accepted by the manufacturer and the applicable ranges of qualification reflected the ranges of ASME Sec IX.
If the persons test was performed without the above, there is no provision in ASME Sec IX that allows a welder qualified under another code to weld.
Have a nice day
Gerald Austin
http://weldingdata.com/