Noise reduction for VIN and VOUT
There are things which can be done to reduce this noise such as adding a boot resistor or snubber, adding input or output caps for high frequency bypass or adding some inductive filtering.
Noise picked up in the measurement
When measuring the output ripple with full bandwidth the measurement technique is very important. Make sure you actually need to measure this with full bandwidth. For measuring the output ripple it's important to minimize the loop area to avoid picking up noise. This can be done by doing a "pigtail" type measurement, using a differential probe or soldering a coax cable directly across the output caps. It is also probably best to prove the ripple as close as possible to the load.
The tech article linked below does a good job discussing this if you'd like some more detail.
If this noise really needs to get reduced, it will likely require some changes to the TPS54A24.
For reducing noise of the TPS54A24, the article linked below might also be useful.