I'm going to refer you to two websites. At the PhilPapers Survey, you'll discover that only 4.8% of "target faculty" said that they accept or lean toward skepticism. Among specialists in epistemology (the theory of knowledge), that figure increases to 9.4%, but it's still small enough to suggest that philosophers in general don't think of skepticism as having the upper hand once the reasons for and against it are examined carefully.
For detailed discussion of your second question, you might start with the SEP entry on "Certainty". I hope you find these resources helpful.