All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Specifying a particular day for shaving the head and believing in its excellence cannot be confirmed except with Sharee’ah evidence. After investigating the matter in the books of the scholars, we have not come across the excellence of shaving the head of the child or anyone else on Wednesday or on other days. Also, we have not come across what you mentioned that the mothers of Imaams Ash-Shaafi’i and Al-Bukhari used to do so with them when they were children. Even if we presume that it is confirmed that the mothers of Imaams Ash-Shaafi’i and Al-Bukhari did so, this is not evidence that this act is a Sunnah, nor does it prove its excellence.
Allaah Knows best.