Collossus 199 Giant Cryptic

It is ill feeling, not I’ll feeling, thank you

I was wondering...

Only sure of the second and last answers. Suggestions for the remainder.

1 Down. The cause of ill feeling, S??????? SICKNESS, maybe
2 Down. Delegates take me back to Austin, e??????s EMPOWERS
8 Down. He has capital ideas, i???s??? INVESTOR, perhaps
9 Down. Round trips, c??????? CIRCUITS, perhaps
12 Across. Essential to supply finances for last word before tale becomes endless, ?u?n?m?n?a? FUNDAMENTAL

Thank you Imur