AP royal oak 33mm full gold mart price?

[rainoo8]

Hi everyone,I am eyeing an AP royal oak 18k full gold 33mm.
The watch does not come with box/papers
It is a D series(Is it from 94-98?)
It is a quartz movement(is it problematic?Must go AP to change battery?)
Servicing costs/parts prohibitive?
The watch is in fairly good condition.
The seller is asking for $9000.
is this price reasonable?
Sorry for asking so many questions.AP noob here.
Thank You.