I am late to this thread, but can I add my 2pence?
He has a bike which is 18 years old - if he is looking for a mechanic to do brake-pads, chains, tyres etc then no problem; but, if he is having problems, then the pros will either steer clear or will charge a lot and if the problem is difficult to fathom it will get pricey quickly.
Can he not get himself on a Ninja forum (one with ZX9R knowledge) and get the lay of the land?
We are a knowlegeable lot on here, could he post exactly what he needs a mechanic for on here and perhaps we could give him useful input so he makes better decisions. It is very easy to throw money at older bikes (or someone else to do so, and to invoice the owner at the end) and not actually resolve things [it's why you see loads of bikes on ebay/gumtree with "not runnning right, probably needs new plugs" - which means 90% of the time "I replaced the plugs and it still won't run right, i give up"].