Is it obligatory to return money gained from cracked software programs to their owners, or to a school if unable to return it to the owners, knowing that this occurred before puberty and before being aware of its impermissibility?

It is not permissible to use cracked software. However, any gain or prize obtained through the use of cracked software is permissible to benefit from, and there is no obligation to give it to the software owners or the school. Rather, it is obligatory to guarantee the rights of the owners of those programs and compensate them for what they missed out on due to their use. The fact that the user is young or unaware of the religious ruling does not affect the guarantee of rights, although it does remove the sin.