Is performing the Tarawih prayer in congregation in the month of Sha'ban, with the aim of training students for imamate and preparing for Ramadan, considered a recurring annual innovation, and what is the definition of innovation?

This method of teaching is subject to hesitation and legal scrutiny, because it dedicates the month of Sha’ban to Tarawih prayers, and there is no evidence to support this. Thus, it falls under the category of an additive innovation (bid’ah idafiyyah). The safer approach is to change it, as it is not the only means to achieve the educational and training benefit.

As for performing congregational prayers for the purpose of teaching, it is permissible in principle. This is indicated by the hadith of Anas, in which the Messenger of Allah (peace be upon him) led them in two rak’ahs, which shows the permissibility of prayer for teaching. This is also indicated by the hadith of Ibn Abbas regarding Jibreel leading the Prophet (peace be upon him) in prayer.