Not getting acknowledgement from MPU 9250 I2C slave using STM32F401RE
Before you search for code problems, you should have a bus properly working. Some devices have built on pull ups, but 10k is rather to high resistance. 

You should enable the MCU pull ups as well, or add another 10k in parallel. 

EDIT:

Now let's see what you get from the scope: 0110 1000, which is 0x68 hex, right? But you should have 7-bit address + R/W bit = 11010000 Somehow you don't shift to the left properly in your program.