how can i get time delay from cross correlation ? Learn what cross-correlation means and the Question will answer itself.
why we substract 99 ? I have no idea. It makes no sense to me, but it's your code, right?
does this value differ if sampling rate changed? Only if you change it.
does this code suitable to detect time delay between two signals? I doubt it.
What do you want us to do with a picture? [Think if I asked you for help and sent you a 4-page listing of Matlab code -- what would you do with it, particularly if there were "crutches" (like an Express VI) that maybe had values hidden inside them?]. You stand a much better chance of getting useful help by attaching your VI.