The *.h file contains only one (by default it is 0x68) address for the sensor. Therefore, the application program will always see (find ) only one MPU9250 as active sensor in the system at address 0x68. This is my understanding. If so, how to operate two or more sensors together?
Let us use the AD0 line (s) of the sensor (s) as selection lines. The value of 10 for the two AD0 lines will select the very 1st sensor (MPU9250-0), the value of 01 will select the 2nd sensor (MPU9250-1), and so on.