There are people claiming that you have to take Ahad Hadeeth into Aqueedah if it Sahih.

If the Aahaad Hadith is such that it is received and excepted by the ummat amalan and qawlan (Ijmaa) then it will suffice. Ijmaa is a Qat'ee Daleel and is sufficient to prove Aqaaid.

According to majority of the Ulama, the authority of a Mutawatir Hadith is equivalent to that of the Quraan. Universal continuous testimony (tawatur) engenders certainty (yaqin) and the knowledge that it creates is equivalent to knowledge that is acquired through sense-perception. Simply, Mutawatir Hadith gives the benefit of positive and definite knowledge in which there is no doubt, therefore Mutawatir Hadith is used in the establishment of Aqaaid.

and Allah Ta'ala Knows Best

Mufti Ebrahim Desai