Does the repentance of someone who stopped praying for nine years and watched pornography, then repented but returned to her negligence in prayer, get accepted? And must she make up the missed prayers, and how can she steadfastly maintain her prayers?

The door of repentance is open, and no matter how great a servant's sin, Allah accepts sincere and truthful repentance. One should not despair of Allah's mercy; rather, one must approach repentance with truthfulness and sincerity. Repentance is accepted as long as the servant has not reached the rattling of death (ghargara).

As for prayers that were intentionally missed, there is a difference of opinion among scholars regarding the obligation to make them up. The more cautious approach is to make them up to ensure that one's responsibility is fulfilled with certainty.