The most common and most likely answer to this crossword clue is the 9 letter word ROLLOVERS
I've seen this crossword clue in The Daily Telegraph
R
O
L
L
O
V
E
R
S
Buddy explains!
The straight part
We know that "Opportunities for big wins" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case opportunities for big wins = rollovers.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 ROLLOVERS mean?
ROLLOVERS noun- The process of incrementing, especially back to an initial value.
- A road traffic accident in which a vehicle overturns.
- A graphic element that changes its appearance when the cursor moves over it.
- A keyboard feature where each key is scanned independently, so that multiple simultaneous keypresses always register correctly.
- The reinvestment of funds in a new issue of the same or similar investment.
- A fee paid by a borrower in order to defer full repayment of a loan.
- In the National or European lottery, the situation in which a jackpot that has not been won is carried over to the next week.
- A target on the pinball table that is activated when the ball rolls over it.