Is it permissible to take the excess money from the store's inventory, at the request of the employee, to compensate for the deficit that the employee pays to the employer, and what are the consequences of that?

It is not permissible to force the cashier to guarantee a shortage in money unless it is due to their negligence. As for an excess in money, it has several scenarios:

If it is due to the cashier as a gift from customers, then they may use stratagem to take it if the store owner forces them to leave it.

If it is due to customers by mistake, then it is a lost item (Luqata), and it is not permissible to use stratagem to take it.

If it is due to the store, then it is not permissible for the cashier to use stratagem to take it.

If the cashier is forced to pay for a shortage without any negligence on their part, then they may use stratagem to take an amount equivalent to what they were wronged by from the excess that is due to the store.