Which number would Mbappe wear at Madrid?

The arrival of Kylian Mbappe at Real Madrid seems to be getting closer and closer. But if his transfer is confirmed, which shirt would the French star wear? Mbappe could choose the numbers 7, 9 or 10.
The No.7 is currently worn by Vinicius Jr and is unlikely to be abandoned by the Brazilian, as a result, it seems impossible that Mbappe will inherit the number of his childhood idol Cristiano Ronaldo.
The No.9 is currently free as Joselu decided to wear the No.14 to start his adventure at the Santiago Bernabeu Stadium but could be worn by Endrick next season when he joins the Spanish giants for good.
Meanwhile, the No.10 is being worn by Luka Modric, whose future at Madrid is uncertain. His current situation is not the best and he could leave as a free agent at the end of the season. The No.10 seems to be the best option for Mbappe as he already wears that number with the French national team.