Every photo has more or less noise. We beat it in post-processing of the RAW image, or then it is done automatically for in-camera JPEGs.
My camera is a very entry level Sony A37. Some time ago I forgot to dial ISO down after a night-time shooting, so I accidentally had it up at 3200 when taking a photo of my daughter the next day.
Normally I use Sony's own Image Data Converter software to convert my RAW files, but as this applies some basic denoising already at import I usually don't see very noisy photos to begin with. So I'll skip Sony's converter for this one.
Opening this same photo in another software, the RAW-Therapee in this case, shows a very different image. The whole photo is nothing but separate dots of color plus some "hot pixels" and whatnot. This somehow reminds me of the sample photo in your question:
I don't really know how to use RAW-Therapee, so I can't show you the best example here. Even so I could easily remove the noise almost altogether. Actually I must have taken some detail away too, softening the photo unnecessarily. Anyway, I was not trying to properly process my photo but instead only wanted to see how the de-noising works. This is what I got:
See how smooth it now looks. Somebody with proper skills and experience would undoubtedly do better job with RAW-Therapee, or using altogether another software, like Lightroom or suchalike. So far I'm committed to using Sony's own conversion tool until I find it limiting myself, already I feel this moment is nearing.
My answer to your question #1: From what I've heard of Canon 7D this looks normal enough.
And to your question #2: Yes, noise is dealt with in post. I would not hesitate to use even the highest ISO levels if the alternative was not taking the photo at all.
I am not sure with answer #3, because I rarely print my photos. Small prints of high-resolution photos should make noise invisible in most cases.