The unit for free-fall acceleration (as well as all other accelerations) is m/(s)^2, by the way, not m/s. m/s would be a velocity.

It would be very noticeable to a great many things, but probably not if you're just walking around. It would be around 1 pound of difference you would feel in your weight.

If you just went to a place where the free fall acceleration was 9.75 m/s^(2), you wouldn't notice any difference unless you measured it. The average American would weigh about 1 lb or 0.5 kg-weight less than they usually do. Just due to eating and other bodily processes, your weight varies by more than that over the course of a day.

There is nothing special about the *exact* value of 9.8 m/s^(2) (or the standard gravitational acceleration of 9.80665 m/s^(2)) other than that it is a standard chosen for convenient reasons. It is just the approximate average free fall acceleration on Earth's surface. The actual value varies over the surface of Earth because it is not a perfect sphere. Not only are there an equatorial bulge and flattened poles, but there is topography like mountains. The acceleration due to gravity decreases with the square of distance from the center of mass, so it is higher at the poles and lower at the equator, and lowest (on the surface) at mountaintops near the equator. Centrifugal acceleration from Earth's rotation also acts to reduce the effective or net acceleration. Centrifugal acceleration is zero at the poles and highest at the equator. Altogether, the average acceleration the equator is about 1% lower than at the poles. The lowest acceleration on Earth's surface is about 9.76 m/s^(2), at the summit of Mt. Chimborazzo in Ecuador.

Now, if something happened to the physical constants of the universe or even just the properties of Earth so that the average acceleration became 9.75 m/s2, that could be significant--quite possibly an "everybody dies" scenario.