If you always use an icd10 code that has an icd9 in the icd9 field the system will send a 9 if the date of service before October 1st. And will keep it as icd10 if the date of service on or after October 1st.
Just make sure:
1. Each insurance has the correct icd code set.
2. Sending ANSI format using the latest version of Revenue Manager