You can recite until maghrib on Friday. It’s a lot easier to do than the whole surah. But if you can recite the whole surah, that too has benefits. Some of the hadiths about surah al-Kahf are mentioned below: Abu-Darda’ (radiyallahu anhu) reported: The Messenger of Allah (salallahu alayhi wasallam) said: “Whoever commits to memory the first ten Ayat of the Surat Al-Kahf, will be protected from (the trial of) Ad-Dajjal (Antichrist).” [Muslim]
In another narration, the Messenger of Allah (salallahu alayhi wasallam) said: “(Whoever commits to memory) the last ten Ayat of Surat Al-Kahf, he will be protected from (the trial of) Ad-Dajjal (Antichrist).”
The Prophet (peace be upon Him) said: “Whoever recites the Surah Al-Kahf, will be given to him on the Day of Resurrection a light that extends from his place to Makkah, and whoever recites the last ten verses this Surah will be spared, when the antichrist comes out, of his trial … “Hadith reported by At-Tabarani. From Abu Sa’eed al-Khudri (radiyallahu anh), who said: “Whoever reads Surat al-Kahf on the night of Jumu’ah (Friday), will have a light that will stretch between him and the Ancient House (the Ka’bah).” [Narrated by al-Daarimi]
“Whoever reads Surat al-Kahf on the day of Jumu’ah (Friday), will have a light that will shine from him from one Friday to the next.” [Narrated by al-Haakim al-Bayhaqi].