Can I take 69 days terminal leave if it crosses into the new fiscal year (without losing 9 days on 1 Oct)?

You should be able to do this. I signed out in mid-Aug and took leave until the end of Oct (~75 days).

Just do 9 days the end of Sep and start the other 60 the beginning of October

I had 119 days of ets leave balance and 88 days leave carry over. My unit could not figure out how to fill out a da 31. By the time it was time for me to ets on date of october 19, i had lost 30 days of leave to use or lose on oct 1st, than sold 60 days on my ets date ' which ended up leaving me with an ets balance of 29 days that would never be used? Maybe the 29 days are left sumwhere on an s1 shelf collecting dust?
Me myself i would have ratherted etsed when they still yuse stop loss. Maybe they would have said you cant ets, go on deployment now, and when get back from deployment my leave form is already signed an approaved.
Instead i etsed in 2013 when service was down sizing and putting people out with no compensation, so units could not understand milper messages and were messing transtision leave all up. .