Generally - yes. Keep in mind that the speed is squared, so you'll need to know either the initial speed and the change or you'll need to have the change is 'how many times has it increased/decreased".
Bernoulli's principle would be useless if it didn't apply to real gasses. What would be the point of having a model/theory if it weren't actually applicable? The quantitative prediction of the ideal model will be off slightly, but it will be in the same qualitative direction as that of a real fluid.
Your question as it pertains to real life, the answer is no. There are complications that limit Bernoulli to being an approximation only. In flow regimes where vicious forces play a large role, ie slow flow of water with lots of walls, or in flow of less viscous fluids like air but are moving very quickly, on the order of M =.5 Bernoulli becomes inaccurate.