Parking in Sion open at 7h30 AM for 2.5 hours

Hello, the title says it pretty much. I am starting a short term (6 weeks) work in Sion and will be working in the center, Mayennets. I start at 8am and stay until about 10. I was intending to use either Coop City's or Manor's parking, but I only now realised that those shops don't open until 8. Are their parkings open before that time ? I tried but couldn't find the info on the internet :(

Thank you in advance.