..the administration of the Thirupathi temple could not have changed without the concurrence of Krishna Deva Raya.
Dear Sir,
The Thirumala temple was a Vaishnava temple before the rule of Krishna Deva Raya (KDR). Maybe the administration changed under KDR's rule, because the Metla Rajas began administering this region during the rule of KDR (Metla or Metlu rajulu were so called bcoz they were administrators of the areas of the
mettus or stairs, including the areas of Srivari Mettu). But the deity at this time was already Perumal.
Krishnadeva Raya ruled from around 1510 to 1530. Am giving below info from some selected inscriptions where the lord is specifically mentioned in the Vaishnavite form. This pertains to a period earlier to that of Krishnadeva Raya.
1) In 1454, one Tallapaka Thirumalacharyalu also known as Thirumala Ayyangar and known for singing various Shringara-kirtanas for Sri Venkatesa, erected a tank at Thirumala on orders from Achyuta Raya. (Source: TTDI.IV.52, Thirumala). (I don’t know if this refers to Annamayya or his son Thirumalayya).
2) An inscription dated 1413 refers to the reading of ‘Thiru Venkata Mahatmayam’ composed and presented to the Lord at Thirumala by Pasindi Venkatatturaivar alias Jiyar Rammanujayyangar. (Source: Ibid.II.95. Thirumala). In 1469 provision was made to start the recital of Thiruvenkata Mahatmayam to the Thirumala deity. (Source: Ibid.V.92.Tirupati)
3) A record of 1339 mentions that Saluva Narasimha Raya Udaiyar constructed the Vasanta Mandapam for God Venkatesa (source: Ibid II.31, Thirumala).
4) A record of 1367 mentions that the Thirupallielluchi festival was celebrated for Govindaraja Perumal of Thirupati and offerings were made for 30 days of margali month (source: Ibid.I.212, Thirumala).
5) A 1281 record mentions that one Mahamandaleshvara Mishraganda Mangideva Maharaja, fixed a golden shikhara over the vimana of Thirumaladeva of Thirumala (Source: Ibid.I.179).
6) A record of 1298 mentions some persons making offerings during Suprabhatam (which means the presence of Suprabhatam sevai in the temple was already existing in 1298). There are also many inscriptions mentioning various sevais like punugukappu, pulikappu, etc, various offerings of taligais, thirupaniyarams and naivedyams of different types and celebrations of various festivals like kaishikapuranam festival, etc.
7) An undated record mentions that the telugu Pallava king Vijayaganda Gopala made a deposit to offer camphor light to God Venkatesa of Thirumala (Source: TTDI, I.67, Thirumala).
Some more sources of Cholas and Pallavas are mentioned here:
Sapthagiri
Please note the presence of a Pallava inscription dated in the 51st year of the reign of Ko-Vijaya-Danti-Vikrama Varman (that is in the year 830 AD), supposedly the earliest inscription or stone record of the lot -- it records an arrangement made for keeping a lamp burning before a processional image installed in the shrine of Tiruvenkatattu-Emperumanadigal.
By the year 880 AD this was definitely a Vaishnava shrine in which the deity was recognized as Thirumaal or Perumaal.
Apparently although Sangam literature mentions the hill Thiruvengadam, it does not mention the existence of a deity. However, Silappadhikaram by the Jaina monk Illango Adigal describes the Vengadam deity as mentioned by Nara sir in the posts above. Which means that by the time of Silappadikaram this deity was considered Perumal or Thirumal.
Interestingly there is an Adi Varaha temple (boar avatara) in Thirumala which is supposedly older than the main Perumal temple. Legends about it are somewhat obscure. Apparently there are / were many shrines on the hills some of which became dilapidated and crumbled. I wonder if the controversy may pertain to the Varaha temple or to some other temple which no longer exists.