If OPEN processing fails, a two character status code beginning with '9' is returned. For example  "9B".

Enterprise Server is configured to use EBCDIC character set and the programs are compiled with the DIALECT(ENTCOBOL) directive.

The "9B" is an Extended File Status Codes

When using ANSI'74 or ANSI'85,  file status codes, the run-time system can return "extended file status codes" which are more specific to the error..

Extended file status codes are of the form:

9/nnn

Where nnn is a numeric value that is the same as the numeric value of the corresponding run-time system error.
When you get a two character file status returned and the first character is a "9" it means that the second character is actually a binary value representing a run-time error and these are called extended file status codes.

If you look in the Help under Extended file status you will find an example.

So in this example the code is 9B which is a  "9" to flag an run-time extended-status followed by "B" in EBCDIC which is decimal 194, so your code is 9/194.

The "194" can be used to find the appropriate message in the documentation..
An extended file status code of 9/194 is run-time system error and message COBRT194 provides more information about the cause.