The most common and most likely answer to this crossword clue is the 9 letter word PREMIERED
I've seen this crossword clue in The Guardian
P
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More clues leading to the result PREMIERED
Buddy explains!
The straight part
We know that "opened first" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case opened first = premiered.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 PREMIERED mean?
PREMIERED verb- To perform, display or exhibit for the first time.
- To govern in the role of premier.
- Of a film or play, to play for the first time.
- To present a film or play for the first time.