How to create rule to redirect an admin after log in to an admin specific node?
My guess would be that your rule weights are not as they should be.  If your rule that matches the admin role fires first and your rule that matches all authenticated users fires second then admins will always be redirected to node/90.

Check on the weights.  In your case, you want the more specific rules (the one for admins) to fire second.  So you need to make its weight larger than the more general rule.

Does that make it work for you?  I don't think you should need a custom module for this...

Also - disable the custom module while you're testing this out, to make sure the two are not interfering.