In a game of slot machines, can you call a payline you bet on "a wagered payline"? I am not sure if it is the payline that is wagered, or my money are wagered on (upon?) this payline.
Dictionary entries for wager as a noun or verb include:
(noun) That on which bets are laid; the subject of a bet
(verb) To bet something; to put it up as collateral
• The gross commission shall be first deducted from the gross amount wagered on each individual pool...
• If the book is balanced in terms of amounts wagered on each side of the proposition, what is the outcome for the sports book?
• The money wagered on these three horses totals $2,000 and is distributed as follows: ...
• “I never wagered upon your honor, Llewelyn. I wagered upon your common sense."
• The new Madison Avenue guard, in contrast, wagered upon the attractiveness of the messages of U.S. popular culture ...
Returning to your question, if you place a bet on a payline, it is reasonable to say you have wagered upon it. Calling that payline a wagered payline is possible, but perhaps a stretch. Calling it a covered payline might be better.