Mbappe will wear number 9 before moving on to number 10, which is currently owned by Modric. Modrid got a one-year contract extension. I expect him to depart the club next season, and Mbappe can take number 10 from Modric. This is similar to when Ronaldo wore the number 9 first.
It doesn't matter what jersey number Mbappe wears with his new club, what matters is his contribution to the team with beautiful goals scored from his feet and head. Real Madrid has honored Modric for one more season, even though this season he has contributed less to the team due to rarely getting playing time, his presence is really needed in the squad to be a mentor for young players. Number 10 will be Mbappe when Modric leaves, he will have to wait for that moment to come. Now he must focus on helping Real Madrid to defend the La Liga and UCL trophies. The opportunity is wide open to win his first UCL trophy because Real Madrid has always been the favorite team to win the competition.
Yes, you are right because the jersey number is actually just sign or number that identifies the player who wears that number on his jersey, this will not affect anything and gives certain advantages.
Most important thing is that now Mbappe has entered the Real Madrid squad and he will be very dangerous goal machine, contribution Mbappe makes to Real Madrid is also guaranteed to be much better because Real Madrid has the support of great players who will become Mbappe colleagues.
With PSG alone, Mbappe was able to show how sharp he can be in attacking and creating goals, especially in the future with Real Madrid, it can be believed that Mbappe skills will be increasingly unstoppable.
But for some reason there is lot of confidence that Mbappe will be able to achieve his dream title in his first season with Real Madrid, many people believe that they will achieve this achievement.
Hahaha, I imagine what wonderful times Mbappe, especially Real Madrid, will achieve in the future.