You can most likely file for and receive your home heating credit before filing your Michigan Form MI-1040, although there's conflicting information on official Michigan websites.
According to How do I file a Home Heating Credit MI-1040CR-7? on the Home Heating Credit Information page:
If you are required to file a Michigan Individual Income Tax MI-1040 submit the Home Heating Credit Claim MI-1040CR-7 with your MI-1040. If you are not required to file an MI-1040, you may file your Home Heating Credit Claim by submitting form MI-1040CR-7 only. The due date for filing a Home Heating Credit Claim is September 30.
However, the How do I file for a home heating credit? page suggests that Form MI-1040CR-7 can be filed separately, with no provision as to whether you must file Form MI-1040 before the home heating credit form:
The quickest way to file your MI-1040CR-7 form is with e-file.
You may mail a completed MI-1040CR-7 to:
Michigan Department of Treasury
Lansing, MI 48956