I can confirm that! Duchovny was phoning in performances before he bunked out for the last 2 series, and Anderson was relegated to the sidelines with Robert Patrick in the lead role (he did a decent job).
My biggest frustration was that when I finally got round to watching the newest film straight after watching series 9, it had absolutely no correlation at all. All the threads that were left hanging after the show were totally ignored, and the film had very little supernatural or weird stuff in it - may as well not have been called X Files, and just set as a random police mystery drama. So if they do do a reboot/restart, it'd have to actually acknowledge the series and what happened in it (especially the deadline specified in the final episode).