They weren't from the TV Movie itself, but an earlier part of the long and winding road.
Spider Daleks were Philip Segal's idea, and formed part of the Leekley Bible, which was a pitch to Amblin. It was quite a radical departure from the established show, including making the Doctor half-human, the Master his brother and Borusa his grandfather.
There was a bunch of concept art, and they also envisioned remaking a load of classic Who stories. The Spider Dalek CGI comes from this period.
Ultimately Amblin passed and eventually it ended up at Universal and Fox, becoming the TV Movie with just a few vestiges of the Leekley pitch remaining.