I shouldn't have played an upbeat song like this just before his bedtime.
I don't think it was such a good idea for him to listen to such an upbeat song before he's about to go to bed.
ーI shouldn't have played an upbeat song like this just before his bedtime.
「彼のベッドタイムの直前にこんなノリノリの曲を流すんじゃなかった」
to play an upbeat song で「ノリノリの曲を流す・かける」
ーI don't think it was such a good idea for him to listen to such an upbeat song before he's about to go to bed.
「彼の寝る直前にノリノリの曲を聴くのは良いアイデアではなかった」＝「聴かせるんじゃなかった」
I don't think it was such a good idea ... で「良い思いつきではなかったと思う」
ご参考まで！
I shouldn't have played such an upbeat song right before bedtime.
I shouldn't have played such an upbeat song right before bedtime.
I shouldn't have played: 「私は再生すべきではなかった」「聞かせるべきではなかった」という意味です。play a song で「曲を再生する」となります。
例文:
"Oh no, I shouldn't have played such an upbeat song right before bedtime. Now he's wide awake!"
（「ああ、しまった、寝る直前にこんなノリノリな曲聞かせるんじゃなかった。もうすっかり目が冴えちゃったよ！」）
カナダ 
アメリカ合衆国 
