What are the NJ laws for salaried employeesbut if I only worked 9 days out of 10 but still put in 78.5 hrs total my boss takes a PTO day. Can she do that?

That is correct, if you take off work, they will use one of your PTO days. And no you do not get paid over time.

What do you mean by "my boss takes a PTO day?" Do you mean that because you were 1.5 hours shy of 80 hours on your time sheet she made you book a PTO for one of the days? If so - did you actually come to work each of the 10 days? How did you end up being short on hours?

I worked only 9 of the 10 day period and came up 1.5 hrs short for a full 80 hr period. She took a PTO day. When I work beyond 80 hrs, and there is plenty of that, I am not entitled to extra $ and that I understand

No, it is not the hours per day, you are to work 10 days, the number of hours per day does not matter.

You missed one full day, so they take one PTO day for the day you missed.

A salaried employee CAN be docked if they don't show up for work. Doesn't matter how many hours they worked overall. If they don't show up on a regularly scheduled workday, they can be docked for the whole day.