Sorting by date & time in descending order?

putting the UNIX_TIMESTAMP will do the trick.

SELECT id, NAME, form_id, UNIX_TIMESTAMP(updated_at) AS DATE
    FROM wp_frm_items
    WHERE user_id = 11 && form_id=9
    ORDER BY DATE DESC

If you want the last 5 rows, ordered in ascending order, you need a subquery:

SELECT *
FROM
    ( SELECT id, name, form_id, DATE(updated_at) AS updated_date, updated_at
      FROM wp_frm_items
      WHERE user_id = 11 
        AND form_id=9
      ORDER BY updated_at DESC
      LIMIT 5
    ) AS tmp
ORDER BY updated_at

---

After reading the question for 10th time, this may be (just maybe) what you want. Order by Date descending and then order by time (on same date) ascending:

SELECT id, name, form_id, DATE(updated_at) AS updated_date
FROM wp_frm_items
WHERE user_id = 11 
  AND form_id=9
ORDER BY DATE(updated_at) DESC
       , updated_at ASC