He wants to offer naafil prayers after praying Zuhr and ‘Asr in ‘Arafah
Question

Is it permissible, after the pilgrim prays Zuhr and ‘Asr with the imam in ‘Arafaat to offer naafil prayers until sunset?.
Praise be to Allah.The Messenger (blessings and peace of Allah be upon him) did not offer any naafil prayer on the day of ‘Arafaat after praying Zuhr and ‘Asr, which he joined at the time of the earlier prayer in ‘Arafaat. If it were prescribed, he would have been keener to do that than us. All goodness is in following his example and his Sunnah. 
And Allah is the source of strength. May Allah send blessings and peace upon our Prophet Muhammad and his family and companions. End quote. 
Shaykh ‘Abd al-‘Azeez ibn ‘Abd-Allah ibn Baz, Shaykh ‘Abd al-Razzaaq al-‘Afeefi, Shaykh ‘Abd-Allah ibn Qa’ood