What do the delay messages mean?

[icepick94]

Example:
Jan 22 09:55:41 zcs postfix/smtp[1163]: BF7A01608844: to=<rdaugherty@wellhead.com>, relay=127.0.0.1[127.0.0.1], delay=9, status=sent
(250 Ok: queued as 0E8CC1608845)
Jan 22 09:55:42 zcs postfix/smtp[6335]: 0E8CC1608845: to=<rdaugherty@wellhead.com>, relay=wellhead.com.inbound10.mxlogic.net[208.65.
144.3], delay=1, status=sent (250 Backend Replied [d13b8794.3079818128.15902.00-041.p01c11m083.mxlogic.net]: .6.0 <114DD3F6-1233-43
3 (Mode: normal))

What does 'delay=9' mean? Does anyone have the list of what the delay messages mean? Does this mean that the mail is queued and delayed indefinitely?
I am having trouble with mail being queued for over 12 hours. I don't know how to diagnose this issue.

[bonadio]

This is how long the message took to be delivered to 127.0.0.1 in you case 9 seconds

[]s