We have previously explained that it is haraam to keep photographs for the sake of memories, and we have quoted the prohibition on that from the scholars of the Standing Committee for Issuing Fatwas and Shaykh al-‘Uthaymeen (may Allah have mercy on him).
The scholars of the Standing Committee for Issuing Fatwas are of the view that video images come under the same rulings as photographic images, so it is not permissible to make these images or keep the video unless there is a need to do so. They were asked:
Does the making of images using a video camera come under the same rulings as making photographic images?
Yes, the ruling on making video images is the same as the ruling on making photographic images. It is not allowed and is haraam because of the general meaning of the evidence. End quote.
Shaykh ‘Abd al-‘Azeez ibn Baaz, Shaykh ‘Abd al-Razzaaq ‘Afeefi, Shaykh ‘Abd-Allah ibn Ghadyaan, Shaykh Saalih al-Fawzaan, Shaykh ‘Abd al-‘Azeez Aal al-Shaykh, Shaykh Bakr Abu Zayd
Fataawa al-Lajnah al-Daa’imah, vol. 2, 1/288
They also said:
It is not permissible to take pictures of animate beings, whether by means of a video, or otherwise, because of the general meaning of the texts which forbade image making and the sternness of the warning concerning it, and the fact that the Messenger (blessings and peace of Allah be upon him) cursed the one who does that. End quote.
Shaykh ‘Abd al-‘Azeez ibn Baaz, Shaykh Saalih al-Fawzaan, Shaykh ‘Abd al-‘Azeez Aal al-Shaykh, Shaykh Bakr Abu Zayd
Fataawa al-Lajnah al-Daa’imah, vol. 2, 1/307
The prohibition on keeping these images is further confirmed because they are images of women that may be seen by non-mahrams; usually the woman in the picture does not want anyone to see it, and these pictures may cause fitnah or problems for the woman in the picture.
You said that the age of some of them was as much as nine years old; at this stage a woman may have reached puberty or be close to it, so it is not permissible for a non-mahram man to look at her.
In the answer to question no. 124208 you will find an example of problems faced by a man – so how about if it was a woman – because of video images taken when he was small.
And Allah knows best.