Yes, it is higher compression. Of course these days new cars have much higher than that, but in its day, 9:1 was pretty high. It basically means that the air/gas mixture compresses to a volume 9 times smalller than the beginning volume when the piston completes the compression stroke. In other words, it is the ratio of volume between the top of the piston and the top of the cylinder head combustion chamber as measures at the bottom of the stroke verson the volume at the top of the compression stroke.
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--Basil
You can lead a horse to facts, but you can't make him think.