The problem with Season 9 of The X-Files is that it tries so hard to answer the questions raised in previous seasons, that paradoxically it seems to answer nothing at all! The last two episodes "The Truth pt 1&2" promise so much from a series that had such a great production team and cast, but they just do not deliver. As an avid fan you may have spent a decent chunk of your life watching every episode in order, just waiting to see the finale... So when you find out that the only answer revealed is a date for the final alien invasion (that nothing can be done to change!), you can't help but feel that you have ben conned into a serious anti-climax. You are not alone here and you can be forgiven for this because most of the final double-episode is spent in a Military court room anyway, not exactly explosive!
Another negative element of series 9 is that three of the best characters in the show (The Lone Gunmen) are killed off in an episode that really does not need them to die! Chris Carter's spin off series "The Lone Gunmen" only survived one series, but it was an original and highly entertaining series that now cannot be taken any further... Ok you might argue that the two shows could be promoted mutually exclusively, but for true fans the continuity would NEVER hold.
Having said all this, I have given this season 3 stars for a few reasons. Firstly, this series does have some first-rate "Stand-Alone" episodes... the problem is that because it advances too quickly towards a conclusion there are not enough of these episodes. Similarly, although I feel that Robert Patrick is a fine actor and takes on the role of Agent Doggett very effectively, I also feel that his best performances and episode storylines were in Season 8. Annabeth Gish does her CV no harm in season 9 either, but again her character really peaked with Patrick's in season 8.
So what of Mulder and Scully? Well, Mulder is in hiding for the whole of season 9 until the last 2 episodes and Scully's character is completely destroyed. What made Scully great wasn't her scepticism throughout the series but her strength; this strength (in my opinion) was burned out half-way through season 8. Overall I think it is a shame because season 9 pretty much falls apart, which is something that has never happened in previous seasons. Having said that, producing an exciting and definitive conclusion to a show as dominant and complex as the X-Files was always going to be a tall order and this season should still be watched once. Disappointing and anti-climactic but not quite a total disaster... you'll probably still enjoy it.