They had to be patient little boys, waiting for the exam results to come out. Constantly going to the gym, spending most of their hours working out. They had well defined muscles.
Compared to 3 months ago, they looked like Kings. They've grown taller, gained great weight that they turned into lean muscles that suited their heights.
Most importantly, they made friends. Great friends that didn't have a problem of their low societal status before they got billions.
During this waiting period, they both called their families, they had to get them to the upper district somehow. So they told an innocent lie. That the academy was holding an end of the term event, they were all needed to attend.
They went as far as to say the school's private jet will pick them up the morning after the schools were closed. They only needed to get to the airport at such and such time. They wanted the surprise to be perfect.