As for performing ablution on the ninth day of Rabi'ul-Awwal, it has been told that this was the act of Ahmad, son of Ishaq Al-Qummi, (the companion of Al-Askari (a.s)), because it was a day of Eid as mentioned in the narrations on the issue that causes happiness for the believers and grief for the hypocrites. And I have found a narration whose chain of narrators on the authority of the Prophet (saw) about the virtue and the blessing of this day, and which states that it is a day of joy for them (a.s) to such a degree that one's mind is amazed. This issue is detailed, and there is a statement on this due to that matter which coincides on this day. Hence we might say that performing an ablution during this day is recommendable based on its recommendation on events such as this, and especially since this day is an Eid for us and our Imams (a.s).
Source: Jawahir-ul-Kalam. Vol. 5, Pg. # 43 - 44.
