If I understand what you are trying to do correctly, there is no need for an Xbox Music pass.
It sounds like you have your own music files stored in your OneDrive Music folder and you want to stream them and/or "sync" them to your phone's SD card storage for offline playing. Here is what you need to do...
1) Open the Xbox music app on your phone.
2) Swipe right to: "Collection", then select "Songs".
3) Change the "showing" filter near the top to "streaming". This will show you only your OneDrive music files that do NOT exist on your phone locally. From here you can stream your songs from OneDrive. Continue on to create a synched local copy for offline playing.
4) At the bottom of the screen, press the "select" icon, then click the "..." to open more options and select "select all". Now you have selected all of your music files from OneDrive that don't exist locally.
5) Press the "Download" icon at the bottom of the screen. It should prompt for a location the first time. Select either your phone or SD card storage.
Keep the music app open and on WiFi while it downloads a local copy of your music. Afterwards, change the filter (step 3) to "all music" since any files cached locally will no longer be considered "streaming". Your playlists will automatically use the local copy if one exists, otherwise it will stream the cloud copy. The locally cached copies will be stored in "\\SD Card\Music\Xbox Music\OneDrive Cache" with random names, but the files are mapped to the OneDrive versions. Repeat these steps anytime you add music to your OneDrive Music folder to sync a copy locally.