I personally think 2 Overlords at 1k is a little much, I would consider using the smaller one that comes with the barge as a standard lord, gives you a new buff and is cheaper. Might give you enough points to add a couple warriors to one of your squads.
I think your Immortals are good with tesla, Gauss is a far more aggressive weapon imo
. Your warriors cover the front lines marching midfield while your tesla immortals sit on objectives.
If you wanted to swing in the far other direction for your immortals a 10 man squad of gauss when paired with an HQ
(say, a lord
) with the veil of darkness can be quite a lethal combination relatively speaking.
Other than all that I think you've got a good list, the detachments should blend well from 8th to 9th, you get 9CP now and when the switch to 9th happens it'll all fit in a battalion so I think youre set