Ulema / hadith confusion on fasting on 9th Zil Hajj

The 9th day of the month of Zil Hajj is the final stage of Hajj, the day when the beloved Prophet (SAW) delivered his final sermon in Makkah from Mount Arafat.  The 10th of Zil Hajj is observed as Eid-al-Adha.

Though the Noble Quran commands us to fast only during the 30 days of the month of Arafat, if someone wants to volumtarily keep nafl fasts on certain other days, it's a good form of additional worship.   The day of Arafat is one of those auspicious days when nafl fasting could be a good idea.  But if one is not inclined to fasting on this day, all one needs to do is not to fast and be silent.  Unfortunately, different ulemas and hadith narrators have said different things on this issue, as a result of which fasting on the Day of Arafat has ended up becoming a controversial issue .. some saying 'yes' and some 'no.'

Check this out:

Imam Shafii said, "Fasting is recommended for those who are not on Arafat on the day of Arafa; as for hajjis, in my opinion, it is better for them to eat than fast because they need strength for prayer on Arafat ."

Imam Ahmad said, "If a person is strong enough to fast on Arafat, he can; if he eats it is alright because it is a day that one needs strength."

Abu Hurayra narrrates:
"The Messenger of Allah (pbuh) prohibited fasting on Arafat on the day of Arafa."

Ibn Umar said: "The Messenger of Allah, Abu Bakr, Umar and Uthman did not fast on the day of Arafa; therefore, I do not fast, either."

Imam Malik and Imam Thawri preferred fasting.

According to other hadiths, Abdullah Ibn Zubayr and Hazrat Aisha tended to fast.

Ata said, "I will fast in winter; I will not fast in summer.”

Qatada said, "There is no drawback to fasting on Arafat unless it makes a person too weak to pray (dua).

Besides, I've also heard some of our scholars saying that fasting on this day is only permissible for those who are not on Hajj.

Then again, someone in Facebook made the following assertion:
"If hajj is on hot days and the weather on the day of Arafa is very hot, it is better not to fast; however, if hajj is on cool and short days, one can fast."