LSM9DS1 accelerometer with too many aux pins. Which ones are actually useful?
This chip looks like Frankenstein's monster. Magnetometer crammed into existing 6D chip and loosely coupled into register map.

Anyway, DEN_A/G and DRDY_M seem to be bugged. Just leave them alone, DNC.

That leaves you with three interrupt pins, one dedicated to magnetometer and two practically identical (i.e. can generate same interrupts) for accelerometer/gyro. You don't really need any of these, unless your MCU is very busy and you want to reduce polling to minimum.

I guess the choice is yours, whether to have two different A/G interrupts or one A/G and one M.