I sprayed WD40 on bushings in my suspension as I was hearing slight noises when turning or going over bumps. ..Then I read this is not good for rubber parts. Should I try to rinse it off with water or should I spray it with something like brake clean (or something else) to get rid of it .

I'd replace the bushing.

Just making sure what you are calling bushings are actually bushings. If they have a grease fitting, they'll probably last a while even after spraying WD-40 on them. Just check for cracking or leaking on a regular basis. If they do not have grease fittings on them, yes WD-40 is not good for them. If they are making sounds, cracking, or loose then replace them.

I actually don't know yet where the sound is coming from. I just thought wD40 would help and I just sprayed it today..but looking further, I should have sprayed silicone spray instead as it is supposed to help. Since WD40 has just been on there for hours, I thought I could just wash it off. I really don't want to take the car in to mechanic just to replace all the bushings if they are working OK...They currently don't seem to not have any damage on them.

I suggest you run it through one of those car washes that does the undercarriage cleaning cycles as you drive in. Then you should be okay.

yes..good Idea. This is easy enough to do.