I typically shoot for around a 1.070-1.075 range
If you're trying to get to 9% ABV, that's your problem right there. You need about 70 "points" of apparent attenuation for 9% ABV. So the OG would need to be at least 1.080, more likely 1.090.
My wheelhouse is generally the 1.070-1.075 range, but I sometimes try to go higher. I think I have some efficiency issues, that I haven't been able to overcome. For example, I attempted to make and Old Rasputin RIS clone and it didn't hit anywhere near the OG numbers I thought I should hit.
15lbs 4oz Rahr PAle Ale
1 lbs American Crystal 40
1 lbs American Crystal 120
8 oz brown malt
8 oz choc malt
4 oz black barley
Correct me if I'm wrong, but for a 5 gal batch I should have been around 1.092-1.094. I had an OG of 1.084. I mashed in at 153, mashed out at 167, fly sparged for 55 minutes using 172 degree water.
I made a 1.5 liter starter using Wyeast 1028 (London Ale) and then added a Safale 05. It finished out at 1.026 and I was expecting that if I hit my target OG. My thought is if I was 6-10 points off my target OG I should have finished out at 3-5 points below my estimated FG which was 1.022-1.025.
It began fermenting at 67 and then raised up to 72 due to lack of temp control.
Don't get me wrong, it tastes good (broke into it two days ago), but I feel it could have been better if my numbers hit closer.
Back to the original thread: I will have to ask if he boiled the sugar separately the second time then added it to the original beer or if he boiled the beer after first fermentation with the new added sugars.