Q: "How authentic is the evolution theory?"
A: It is a completely "authentic" scientific theory.
Q: "Since not every one is a scientist, i want to know that how does the 'scientific community' rates the evoltion[sic evolution] theory".
A: There are about 5,8000,000 scientists in the world, and about 700 of those who do not accept evolution.
Q: "Is it 100 % accepted or are there few question marks"
A: See above answer -- the percentage that finds evolution unacceptable are 0.00120689655%
To put that number in perspective -- There are more biologists who have the first name "Steve" than there are scientists of *any* discipline who do not think evolution is supported by the evidence...
http://ncse.com/taking-action/project-steve
Your remarks about what "90% of the population worldwide believes..." are irrelevant. Science is about gathering evidence through observation, identification, description, experimental investigation, and theoretical explanations of phenomena. Science is not determined by popular opinion.
Just because someone believes in a higher-power does not mean that they cannot reconcile observable facts with their beliefs. My brother is a pretty devout Christian who believes that there is a God, and he also accepts that evolution occurred. He often makes the point that God is omnipotent, and therefore could have created the entire universe 1 second ago - complete with 13.7 billion years of backstory... and we would not be able to tell - because that's what omnipotent means...
Biological evolution is defined as any genetic change in a population that is inherited over several generations. If you are still asking this question in biology, you are likely failing your class, because you are not paying attention and need to hit the books rather than wasting time on Yahoo! Answers...