OP,
He is ripping you off to such an extent I can only imagine how irritating it is.
900 for a job that should cost a fraction of that.
For a competent person, I would think that is 1 days work on the absolute outside, including collecting the materials.
400 sounds a reasonable amount.
Personally, I wouldn't hire anyone I know to do a job in my home.
From those that I know that have done it, they felt compromised when it came to not being completely happy with the work done.
I am fussy, I always make that abundantly clear to anyone who does a job for me...BEFORE they start....so there isn't any confusion, on THEIR part.
It has served me very well.
It's your home OP.
Its your money.
Keep friendships out of it.
You will save yourself a lot of grief.
I certainly wouldn't trust this guy, who is so clearly prepared to rip you off doing a very basic handyman job.