" 1) new 9 spped cassete which is compatible with wheel (shamano hg50 11-25)"
I don't see an 11-25 listed.
The reference I see for your bike is that it comes with a SRAM 850 12-26, 8 speed?
If you are going to an 11T cog, I think you MIGHT also have to switch to a compact Freehub?