Hi Willy, welcome to the forum!
While I used to work for a race trainer(long time ago when I was young), I'm not into racing at all now & there are other members that perhaps can - was going to suggest
(but see she's already checked in & will be back) and maybe
How experienced are you with training/keeping horses? Is it just racing you're new to?
I'm surprised you can't find anyone local, because I thought the Saudi's were very big on racing - I'm sure there have been Sheiks who have brought their horses to Australia for our big 'Melbourne Cup' before. Or is it that most of them race Arabian horses not thoroughbreds? I wouldn't imagine technique etc would be any different on that note, but could be wrong.
I can give some info on some of your questions tho...
1. When to start training a 2 years horse on track and when I can register it in an official race?
2yo horses are still babies(well, young teens if compared to human maybe), and while it is extremely common these days for them to be raced at 2yo, it is widely recognised now that this can be way too stressful on their growing bodies. So that kind of answers your No.9 question. But further to 9. if you build up gradually, get the horse strong & fit before doing any real galloping, that will help him become strong enough to hopefully cope well with the stress. Also ensuring good nutrition, feeding, and really good hoof care(including avoiding conventional shoes where possible) are other factors to consider.
and should we use the whip?
5. How/ when to use the whip? how to teach him not to be scared of it?
Most use a whip, but it is a personal thing. Good trainers/jockeys can get horses to run perfectly well without it. I remember one Melbourne Cup winning trainer - a famous trainer who had had many, many wins(Bart Cummings, if you want to look him up) - being questioned by a journalist who asked "I noticed your jockeys don't use whips - why is that?" and Bart replied "Well son, I've noticed that horses don't actually LIKE being whipped." Which in part answers your No.5. The point of a whip is to cause the horse to run harder because of the pain it causes. So you don't want to desensitise the horse to it.
11. Do all racehorses eat the same or it can change from a horse to another?
Most racehorses are fed a lot of 'concentrates' such as grain, over a few meals daily(horses need to be fed little & often) and some hay or grass. It is commonly thought by racehorse people that they need this 'high octane' food, and little hay, but there are those who give their horses a more natural diet & still do very well. Again, another famous, very successful Melbourne trainer is Gai Waterhouse(one of the few women that have managed in the 'men's club' of racing) is one who feeds & manages her horses a lot more naturally than most. The men all scoffed at her, until her horses started beating theirs!