Please find the output requested.

select *
from v$nls_parameters
where parameter = 'NLS_DATE_FORMAT';

NLS_DATE_FORMAT DD/MM/RR

select sysdate from dual;
7/7/2009 2:01:27PM

select to_char( sysdate, 'dd.mm.yyyy hh24:mi:ss' ) from dual;
07.07.2009 14:03:12

select to_char( sysdate, 'dd.mm.yyyy hh12:mi:ss am' ) from dual;
07.07.2009 02:04:17pm

I am using:

select trunc(datetime, 'HH24'),moid,fr,f

from schema.table where
datetime between trunc(sysdate)-1 and trunc(sysdate)-1/24
order by moid, trunc(datetime,'HH24')

I've also tried using only datetime instead of trunc(datetime,'HH24').