I would agree with MDB your loss is complicated and these are notoriously difficult to fit, but not impossible! Although I live in the UK and unfamiliar with Costco Kirkland 9.0 tis essentially the Phonak Marvel, I wore the Marvel 90 13’s for 2 years and they are excellent aids, I upgraded to the Paradise 90’s last week and they seem crisper with a slightly different sound with multiple Bluetooth connections as opposed to a single Bluetooth connection with the Marvels, I am unsure if Costco have the Paradise alternative as yet? I am so far happy with my upgrade, but it will take a week or so for me to access them correctly, but so far so good. Good luck, cheers Kev