Log:

146  data work.date;
147     date_const=put('13mar00'd,date9.);
148  run;

NOTE: The data set WORK.DATE has 1 observations and 1 variables.
NOTE: DATA statement used (Total process time):
      real time           0.01 seconds
      cpu time            0.00 seconds

Commentary:
The PUT function always returns a character value. In this case, the variable date_const will be defined as character with a length of 9. The following output is created and Proc Contents reveals the type and length of the new variable.

Output:

WORK.DATE

Proc Contents for WORK.DATE: