No. In the db the parameter is
SQL> sho parameter compatible

NAME_COL_PLUS_SHOW_PARAM TYPE
---------------------------------------------------------------- -------
VALUE_COL_PLUS_SHOW_PARAM
----------------------------------------------------------------------------

compatible string
9.0.0

BUT I tested one more time in a 9.2.0 db and it finally works. So I guess nothing wrong with the syntex just the db has to be set properly. I really don't think rename only works in 9.2.0 but that is what it seems for now..

SQL> sho parameter compatible

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
compatible string 9.2.0.0.0



SQL> alter table test1 rename column b to a;

Table altered.