According to the Minecraft Wiki, Pillagers were added in beta 1.9.0.0. I am on beta 1.9.0.3 and I can't seem to find a spawn egg for the Pillager. I think this is not a bug, but rather a technical issue, or it's found on Experimental Gameplay. (The wiki states nothing about it being on Experimental Gameplay.)
MCPE-40399
Pillager Technical Issue
Resolved
Cannot Reproduce
0
(Unassigned)
Unconfirmed
Phone - Android - LG Other (Specify in description)
Android 6.0
1.9.0.3 Beta
Retrieved
Don't reply to this bug anymore because I now know why it wasnt present. It was on Experimental Gameplay.