No, it even isn't Sunnah
There is no evidence from the Sunnah that the Prophet intentionally ate an odd number of dates.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said:
It is not obligatory – and in fact it is not Sunnah – to break the fast with an odd number, three or five or seven or nine, except on the Day of Eid al-Fitr, as it is proven that the Prophet (blessings and peace of Allah be upon him and his family) would not go out for prayer on the Day of Eid al-Fitr, until he had eaten some dates, an odd number thereof. Apart from that, the Prophet (blessings and peace of Allah be upon him) did not seek deliberately to eat an odd number of dates.
[Fataawa Noor ‘ala ad-Darb (11/2)]
There is a hadith where it says that the Prophet ate 3 dates to break his fast.
The Prophet (blessings and peace of Allah be upon him) used to like to break his fast by eating three dates or something that had not been touched by fire.
Narrated by Abu Ya‘la (3305)
It is a da‘eef (weak) hadith that has not been proven. See ad-Da‘eefah by al-Albaani (966).
However, some scholars say that it is mustahabb to make everything odd-numbered.
Shaykh Saalih al-Fawzaan (may Allah preserve him) was asked:
Should making things odd-numbered be done with regard to all permissible things, such as drinking coffee and the like, or is it only with regard to things concerning which a text has been narrated?
The Shaykh’s answer may be summed up as follows:
All words and deeds should be made odd-numbered. This is the Sunnah.
Shaykh ‘Abd al-Kareem al-Khudayr (may Allah preserve him) was asked:
Will we be rewarded for making things odd-numbered as an act of devotion when eating, drinking and so on?
Yes, we will be rewarded for doing that as an act of devotion. So if a person eats dates, he should eat one, or three or seven, an odd number, because Allah loves that which is odd-numbered.
‘Abd ar-Razzaaq (5/498) narrated from Ma‘mar, from Ayyoob, from Ibn Sireen, from Abu Hurayrah, that the Prophet (blessings and peace of Allah be upon him) said:
“Verily Allah is One and loves that which is odd-numbered.”
Ayyoob said: Ibn Sireen liked that which was odd-numbered in all things, to the extent that he would eat an odd number of things. This is a saheeh isnaad.
To summarise, the matter is broad and has not been proven. The scholars who said that said it on
the basis of ijtihaad.
And Allah knows best.
Source: Islam Q&A