I wanted to know how much my paychecks will be i will get paid 9 dollars an hour to start and i will be working 7 days a week 8 hour shifts.?

This is assuming you are single, have no dependents and are not taking any exemptions, and live in a state with no state or local income taxes.

7 days at 8 hours per day = 56 hours per week. 40 hours would be paid at $9 per hour, and 16 hours would be paid at the overtime rate of $13.50 per hour (time and a half).

So your gross pay would be $576 for the week. From that, they will deduct $71.18 for federal income tax, $35.71 for Social Security (FICA) tax, and $8.35 for Medicare tax. That would give you a take-home pay after taxes of $460.76.

Note that this also does not include any deductions that are specific to your situation, like uniforms and tools, health insurance, retirement savings, union dues, and similar. Some or none of those may apply to you.

General rule of thumb is that taxes take about one third of your gross pay. But it also depends on whether you are paying a state tax or not. You also have to factor in time and a half if you are getting that after 40 hours in the work week...