for some circumstances I will not be able to write jee main Sept 2020. even though I will not be writing exam will it be considered as my first attempt or they will just put me adsent
If you are absent from 2nd session then your 1st attempt i.e. January session score/percentile will be considered and rank list will be prepared based on it then it will be processed further for counselling process.
there won't be any issue regarding it. it would be better if you clear your doubt from the NTA help desk if you want clarity.
Hope it helps!