JCL is not
, repeat not
, a programming language. There is no defined method in JCL to get the date and time. Even if there was a method, you run into the question, which date and time? The date and time the job entered the system? The date and time the JCL was initially validated? The date and time the job actually started executing? Local date and time, or some other date and time?
Some system variable data is available for started task JCL. All user jobs have access to the userid used to run the job, but that's about it.
//MYSRC DD DISP=SHR,DSN=&SYSUID..SOURCE