Is it valid for a person who resides in Saudi Arabia under a work contract to perform hajj during the hajj season?

There is difference between the validity of hajj and its permissibility. Hajj is valid if its pillars and obligatory elements are met; it fulfills the obligation if it is the person’s first obligatory pilgrimage, and it counts as a supererogatory hajj if it is not.

As for its permissibility, it is a separate matter. For example, if the terms of the contract do not permit you to perform hajj, yet you go against it and perform hajj, then you have committed a sin for breaching the terms of the contract and for the potential harm this may cause to yourself and others.

Nonetheless, your hajj remains valid as long as its pillars and conditions have been properly fulfilled.

And Allah the Almighty knows best