I dunno if it's cut and dry like that. The math makes assumptions -- velocity of lightsaber = 0, temperature of lightsaber is constant, angle of bullet through lightsaber = 90*, velocity of bullet is constant, velocity vector disruption = 0 (after melting and exploding, no less), even heating, etc. 9mm bullets get deflected by regular old glass, like, on the regular -- are we taking elasticity of the blade into account? What about the bullet's drag coefficient, which is altered as the bullet deforms and amplified (possibly significantly) by the plasma of the blade? 

IOW, what we really need is a demonstration. Preferably by an actual proficient force user. Too many variables are ignored here -- I think it's entirely possible that a lightsaber can block 9mm bullets (well not [b]entirely[/b] possible, I guess, but.... shut up). Of course it begs the same question as blocking arrows with a sword -- if you're so fast you can do that, [i]why not just get out of the damn way?[/i]