I am not an expert in this stuff and speak only from what I can gather from others in similar positions.
The first thing to understand about the grade system is that everyone earns differing amounts. If you work for the Cabin Crew side you generally get more than most other departments. The Flight Ops side does a bit better than other departments as well, but it is hard to define what the pay structure is. (Its all top secret) As a Grade 9 your privileges are the same as a First Officer, i.e housing, staff travel and provident fund. Specifically, Apartment accommodation if you have no kids, Business class sub-load travel and 12% of salary contribution by company towards a somewhat pathetic provident fund. You contribute 5% to the same said fund from your monthly wage.
As to your actual wages, and I am guessing here, they could range from as low as 12,000 AED up to maybe as high as 18,000. If I was guessing I would say about 16K per month.
Living on a grade 9's salary is not easy here, if you do join make sure you NEVER move out of company accommodation. Good luck.