Hi mate,
Yes it is very possible to get a passport without going through an agent
The duration here is what matters because after you've made the payment
electronically, you would then be given a date for appointment at the
regional office, after which might take up to a month or thereabout
before you get your passport.
But i would advise you go through someone you know thats working
at the immigration centre passport department to help you in the
processing of the passport because this don't really take much time and
it depends on how fast you want it that matters.
Let me know where you stay so i can know if i will be of help
because i know of someone who works there but he's office is in
Ogun State capital, Abeokuta, who can get it done for you as specificied
by you, and if Abeokuta is a place you can visit, then get back to me on my email
so i can give you details on how to get in contact with him.
oloksbeejay@yahoo.com . thats my email address. hope am able to answer your
question. Cheers