Can we measure when masses attract each other,with what speed?

Relativity does not have masses "attract" each other. Gravitation is not a force.

Spacetime that is made by each bit of matter, orbits with that matter. So the "line of action" between Jupiter and the Sun, aligns with Jupiter's position *now*... and no c delay.

The "speed of gravity" should we figure out how to push matter out of this Universe, is expected to be c. But we cannot test this via collisions, black holes, and such.

If you mean to ask ''the speed of gravity'' - as best as it can be determined, the mathematics and models point to gravity either being propagated at the speed of light, or, being a property of the 'fabric' of space-time - it has no 'speed' per se.

Planetary objects are made up of smaller objects - - **all** of which have mass.

You have mass. I have mass.

All these objects attracted each other and all other objects in the area - before and after becoming a planet.

Objects don't magically "develop mass". The mass has to come from somewhere, and it brings gravity with it. The gravity it brings travels at the same speed as the object.

CHANGES in gravity can come from very rapid spinning of a *very* massive object -- about the mass of our sun. Or when two *very* massive objects collide. These changes in gravity move at the speed of light.

Yes, we can measure this.

Yes, gravitational theory is very precise in determining the attract force between objects with mass. It is this knowledge that allows astronomers to measure the effects of one planet on another and to predict where non-reflective objects (such as planetesimals, moons, or even other planets) might be.

Gravitational force is proportional with mass, so that if we know the mass of an object, we know how strong its gravitational force is. However, it's often the other way around: we find out the mass of a planet or moon by observing its gravitational effect.