How to assess the chance to get accepted to a master's program in the United States?
I don't think that there's a huge enough discrepancy between the technical content of the European three-year bachelor's and the four-year American bachelor's to make that a big concern. 

However, where you may run into problems is that your GPA might not be considered competitive for a top program, if it's only in the 8.0's out of 10. (It might get translated to a 3.3 or so, which would be problematic.) What will make up for this is some statement that you're near the top of your CS cohort, and good letters of recommendation will also help.

Where you'll also need to do some research is on whether the departments you want to apply to offer terminal master's programs; if not, it will make it a little more difficult, as the expectation would be that if you are admitted to the master's program, you will then continue on to the PhD program thereafter. (At such schools, a stipend is typically offered during the master's phase of the program; at schools that offer a terminal master's, the funding sources for the master's degree-only candidates is usually quite distinct, if it is available at all.)