Warhammer 40k traitor legions-favored of tzeench special rule
Yes, if the Sorcerer/Exalted Sorcere was bought as part of that Formation
and the formation met the criteria of the rule (i.e. if the formation contains the maximum number of units).

The Sorcerer/Exalted also gains Fleet as per the Formation special rules.

Unless otherwise specified, all units/models in a formation are subject to the special rules of that formation.

Source: Wrath of Magnus, p 150 - Tzaangor Warherd.

Also, from the Main Rulebook, p 118 - Formations text box:


  Formations
  ...the Army List Entries that comprise a Formation are listed on it, along with any special rules that those units gain...