I need to make sure I understand 1002.9 correctly. 1002.9(b) that discusses adverse actions for business applications only, really only pertains to how the notice must be delivered and what info is included, right? The rest of 1002.9 (c-e) would still apply, meaning we still need to send notice to a business applicant if they submit an incomplete application?

I assume you are referring to 1002.9(a)(3). Notice what it states:

"For business credit, a creditor shall comply with the notification requirements of this section in the following manner:"

I interpret this to mean if you comply with what is listed in (a)(3) for a business credit application then you have satisfied the requirements of 1002.9. This means a notice of incompleteness is not needed for business applications.