On macOS the keychain allows me to view all certificates and if I want manually revoke trust to a certificate. I was wondering how I could do something similar on my iPhone as my school forces me to install their intermediate certificate to use their Wi-Fi, which I would like to revoke when not at school to prevent the school from man in the middle attacking/creating fake SSL certificates for websites I view outside of school.
You can find certificates installed on your device in Settings → General → About → Certificate Trust Settings. Here you can switch root certificates on and off as you please.
As shown by the small words in the screenshot, certificates enforced by a profile can't be modified here. Profiles are installed in Settings → General → Profiles. You can't turn such certificates on/off — instead you have to uninstall and reinstall the profile.