There is a bar or some device that is there to prevent your stuff from sliding forwards. I’ve not been crawling on the airplane floors enough to see any weight rating on it but I would bet money on it being crash tested and rated according to whatever the overhead compartments are.
Then how do you explain the 8kg weight limit for carry on? Who is endagered by 9kg luggage? And it’s not even handled by the staff.
The overhead compartments have a weight limit because they must be designed to keep the stuff in there during an emergency.
No weight limit under the seat, though.
There is a bar or some device that is there to prevent your stuff from sliding forwards. I’ve not been crawling on the airplane floors enough to see any weight rating on it but I would bet money on it being crash tested and rated according to whatever the overhead compartments are.