According to recent leaks, Jujutsu Kaisen was in danger of getting cancelled due to the low reception it received during the initial arcs.
So, Gege Akutami, the author of the series, had decided to permanently kill Yuji in Chapter 9 and wrap up the manga if the series had been cancelled.
Furthermore, in 2021, he stated that he does not mind killing any character as long as it makes the story interesting.
About Jujutsu Kaisen:
Jujutsu Kaisen is a Japanese manga series written and illustrated by Gege Akutami.
It has been serialized in Shueisha’s shōnen manga magazine Weekly Shōnen Jump since March 2018, with its chapters collected and published in 25 tankōbon volumes as of December 2023.
Studio MAPPA brought the world of JJK into anime by airing 24 episodes of season 1 from October 2020 to March 2021 and a second season that premiered in July 2023.
Crunchyroll describes the overall plot of Jujutsu Kaisen as:
Yuji Itadori is a boy with tremendous physical strength, though he lives a completely ordinary high school life.
One day, to save a classmate who has been attacked by curses, he eats the finger of Ryomen Sukuna, taking the curse into his own soul.
From then on, he shares one body with Ryomen Sukuna.
Guided by the most powerful of sorcerers, Satoru Gojo, Itadori is admitted to Tokyo Jujutsu High School, an organization that fights the curses… and thus begins the heroic tale of a boy who became a curse to exorcise a curse, a life from which he could never turn back.