The MPU-9250 can be powered by 5V because the module has an on board regulator. However, it is a 3.3V device and the inputs can never be exposed to 5 V.
The best option is to connect the MPU-9250 directly to a 3.3V Arduino.
The second best option is to use a two channel 5V to 3.3V level shifter to connect SDA and SCL to A4 and A5 on a 5V Arduino.
The third best (one that works ONLY with I2C connections) is to use pullup resistors (2.2K to 4.7K) connected from SDA and SCL to 3.3 V.
Hint on posting links: this is all you need.
All the rest is tracking your personal activities.