No, observers in different reference frames would not necessarily agree that the clock indicates 12:00:00 when the ball hits it. The concept of simultaneous events depends on the observer's reference frame and the relative motion between the observer and the events being observed.
According to the theory of special relativity, the notion of simultaneity is relative and can vary between different observers moving relative to each other. Time dilation and length contraction effects come into play when objects are moving at relativistic speeds.
If the ball is moving at a significant fraction of the speed of light, the observers in different reference frames will perceive different timings for the ball hitting the clock. For example, an observer moving relative to the ball and the clock may see the ball hitting the clock before or after the clock shows 12:00:00 due to the effects of time dilation.
In summary, observers with different reference frames will not necessarily agree on the timing of events, such as when the ball hits the clock, due to the relativistic effects of time dilation and the relativity of simultaneity.