Connected to:
Oracle9i Enterprise Edition Release 9.2.0.6.0 - 64bit Production
With the Partitioning option
JServer Release 9.2.0.6.0 - Production

SQL> select value from nls_database_parameters
  2  where parameter = 'NLS_NCHAR_CHARACTERSET';

VALUE
--------------------------------------------------------------------------------
AL16UTF16

SQL> CREATE TABLE NCLOB_TST(COL1  NCLOB);

Table created.

SQL> insert into NCLOB_TST values ('12/31/2000');

1 row created.

SQL> column col1 format a12
SQL> column col1_ddmmyyyy format a12
SQL> select col1, to_char(to_date(col1, 'mm/dd/yyyy'), 'dd/mm/yyyy') col1_ddmmyyyy from NCLOB_TST;

COL1         COL1_DDMMYYY
------------ ------------
12/31/2000   31/12/2000

SQL>