The most common and most likely answer to this crossword clue is the 9 letter word RELIGIONS
I've seen this crossword clue in Financial Times
R
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The straight part
We know that "such beliefs" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case such beliefs = religions.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does RELIGIONS mean?
RELIGIONS noun- Belief in a spiritual or metaphysical reality (often including at least one deity), accompanied by practices or rituals pertaining to the belief.
- A particular system of such belief, and the rituals and practices proper to it.
- The way of life committed to by monks and nuns.
- Rituals and actions associated with religious beliefs, but considered apart from them.
- Any practice to which someone or some group is seriously devoted.
- Faithfulness to a given principle; conscientiousness.
- Engage in religious practice.
- Indoctrinate into a specific religion.
- To make sacred or symbolic; sanctify.