It is legally okay provided you work for 5 days in a week. At the same time if you have six days in a week, you will be working for 8.5 X 6 or 51 hours which is not allowed. Now, a day of 9 hours or 8 hours and 30 minutes excluding lunch time is okay for a day or two but when it crosses 48 hours, it cannot be right as per law. If you work for more than 48 hours a week, normally employee will be eligible for overtime wages.
However, nothing above stated will apply to persons holding managerial responsibilities and powers. Moreover, in any service organisation you can have flexible work timing wherein this 9 hours' working can be interpreted as 9 hours of spread over. Spread over means the total hours an employee spends in a workplace and this would include the intervals for tea, lunch and other entertainments. If you have 30 minutes lunch and say 15 minutes each for morning and evening tea, naturally, the working hours will be 8 hours only and then the time will be within law. Obviously, in an office which is entirely different from a factory set up where each idle time is recorded and a worker going out of workplace is recorded by means of outpass, this will not count much. However, for legal aspects this 30 minutes will make difference.
Madhu.T.K