I'd fight this to the bitter end, especially if traffic school is not an option. If it IS, then I'd ask for a reduced fine (financial hardship or some tra-la-la) and go to school.
It's all about how much time you have and how you feel about, er, stretching the truth. I *wouldn't* (hypothetically speaking, of course) be against lying through my teeth and casting logical (and illogical) dispersions about the officer, his method of "clocking you", his refusal to let you see the gun, his general emphasis as to your real speed "your honor, he kept saying "ABOUT 90 mph"", etc etc. You could (and should) admit that you were speeding, but nowhere NEAR 90mph "heck your honor, my speedometer doesn't even GO that high". The last three times I've been pulled over for speeding I got a warning simply because my very first words were a humble admittance to speeding and total cooperation.
It seems to me that if you were traveling 88mph you would be facing a VERY different set of circumstances. So often the idea of the state being responsible for the burden of proof gets sidelined in traffic court. It still remains, though - make that rat PROVE he got you at 90mph. Although in a word-against-word decision the cop always gets preferential treatment, throw some dubious questions out there and then ASK for a reduced ticket. Make sure they understand that you WILL go to trial if they don't offer a lesser (say, 85mph) ticket. Let them save some face too.
And if they don't go for it, ask for a trial - you're entitled to one and the cop will have to PROVE to a jury 'beyond a reasonable doubt' that you were indeed travelling in excess of 90mph. IF he can't do that through hard evidence you're off. Total dismissal. All you would have to do is cast enough doubt and play the righteous won't-let-the-incompetence-and-omnipotent-attitude-of-our-police-force-make-me-an-innocent-victim role. How can you lose with the right attitude?
If for some longshot reason you DO lose, what's the difference? You still get four points and a fine. It's almost as if you can't afford to NOT fight it.
Then again, depends on you. I personally think that on an open highway in good conditions a speed-trapping oink with a radar gun is the real crime.
Fight the power and question authority.