Is the Badrinath Temple originally a Buddhist place of worship?

 Yes. May be.

1.According to some accounts, the temple was a Buddhist shrine till the 8th century and Adi Sankara converted it to a Hindu temple.

2. Other accounts relate that it was originally established as a pilgrimage site by Adi Shankara in the ninth century.

3. It is believed that Shankara resided in the place for six years from AD 814 to 820. He resided six months in Badrinath and the rest of the year in Kedarnath.

4. He discovered the deity of Badrinath in the Alaknanda River and enshrined it in a cave near the Tapt Kund hot springs.

5.A traditional story asserts that Shankara expelled all the Buddhists in the region to the other side, Tibet, with the help of the Parmar ruler king Kanak Pal. That may be the reason to believe that it may be a Buddhist Shrine.

6.The temple is revered in Nalayira Divya Prabandham (4000 verses on Lord Vishna in Tamil- a holy text of Sri Vaishnavites), in 11 hymns in the 7th–9th century Vaishnava canon by Periyazhwar and in 13 hymns by Thirumangai Azhwar. It is one of the 108 Divyadesam (like Thiruvananthapuram) of Sri Vaishnavism sect dedicated to Vishnu, who is worshipped as Badrinath.The temple is referred as Tiruvatariyaacciraamam in Tamil literature.

7.Today also, the selection of priest is done after consultation between Garhwal and Travancore royal families.

North view:

Yes to add to your comments

There was no temple system in vedic system, temples are not build in India in ancient India specially in north Indian.The construction was only started by Buddhist and if a close look at these Badrinath, kedarnath, Shankaracharya temple in Srinagar - their structure clearly resembles of Buddhist monasteries all over the world... In south there was Hinduism but in north Buddhism is popular... The word to word mouth to mouth campaign Started by shankaracharya did the trick just like in movie dhrishyam.... So that people believe what was told to them... Even Shiv was called as Shankara after Shankaracharya name...... If Hinduism was already there in north what was the need that people come and propagate Hinduism...