Is it possible to use multiple partition with the same route domain ?
Yes, you can have multiple partitions using the same route domain.
Typically used to control administration of different environments within the same route domain.
Check out: https://devcentral.f5.com/questions/use-cases-of-routing-domain-and-partition-57935
Note that a partition will only see objects created in it and the parent. For example, if you have partitions mystuff-production and mystuff-test, both with parent Common and configured for route domain mystuff-rd, mystuff-production will see objects configured in itself and Common but not in mystuff-test.
It is recommended to configure each route domain in the separate partition in F5 LTM.