Right now the iCloud Music Library doesn't support songs with a bit rate of 96kbps or less. It is likely that the songs are already AAC type when you imported the CD or songs, but the bit rate is lower.
To check what version your songs currently are: Select one of the songs and right click it and select: Get Info. Then select the File tab. You will see the Kind and the Bit rate. If the Kind is AAC but the bit rate is lower than 128 kbps, then this is the problem.
Close that Get Info panel and do the following to convert the song files:
From the iTunes menu, click: iTunes - Preferences - Then click the General tab. Then click the Import Settings... button.
For "Import Using": Select "AAC Encoder" and for "Setting: Select High Quality (128 kbps)". Then select OK to save and close your changes.
Once you are back at your songs, simply select them all and from the top menu choose: File - Convert - Create AAC Version. (The songs will be recreated with the right type now and onwards.)
After the conversion is complete for each song selected, you will have two copies of each song.
Select the first one of each of them (the one with the slash thru the cloud) and delete them. (The newly converted version will likely have a cloud next to it with a dotted outline.)
Once you only have the one song each, you can optionally double-check the file type by right clicking one of them and select Get Info and under the File tab, you should now see: AAC as the Kind and bit rate as: 128 kbps
You can then create your playlist if you haven't already done so. It may take 5 or so minutes for your playlist to show up on your iPhone or other devices as there is a lag.