How can I get all 9 digits of precision in systimestamp?

We have a database with a very high volume of inserts being done in a short amount of time. I need to be able to order those inserts by when they happened.

I added a created_date timestamp(9) column and am populating it via an on-insert trigger with "systimestamp". However the last three digits are always just '000'.

I can see this also via simple queries like:

select systimestamp(9) from dual;

returns: 7/10/2025 11:03:15.869954000 PM -07:00

select TO_CHAR(systimestamp, 'YYYY-MM-DD HH24:MI:SS.FF9') from dual;

returns: 2025-07-10 23:05:31.453045000

how can I get those last three seconds digits? Maybe it is an Operating System limitation? We are running our Production database at version 19.26 on RHEL8 on Oracle Exadata at Customer site hardware.