Is 7500 RIM is good salary for Master Scheduler ?

First 182 days (tax non resident) you pay a flat rate of 25% i.e. RM1875 per month

Then salary RM 90k per annum - Tax RM 9550 per annum or RM 780 per month

Overpaid tax can be claimed in March 2016.

Tax steps on annual salary are:
                 2015
0-5,000                    0%                                                 
5,000-10,000      1% RM50
10,001-20,000    1%  +RM50
20,001-35,000    5%  +RM750
35,001-50,000   10%  +RM1,500
50,001-70,000   16% +RM3,200
70,001-100,000   21% +RM6,300
100,001-250,000  24% +RM36,000
250,001-400,000  24.5% +RM36,750
Exceeding 400 000  25%  (+?)

As you dont say if you will be having EPF deductions or health insurance, cant get loser than this.  If you have any benefits in kind - they will also be taxed.

Its not a great salary if you are single. Expenses will be  about RM2500 per month. i.e. RM1k for shared accommodation, utilities/internet RM 100, Telephone RM100. Travel RM100 + eating out and entertainment. If you want to live alone then minimum RM1.800 for a studio RM75 for utilities, RM250 for internet, tv. + variables above