Yes....my 7 year old drove on a track by himself.
More than likely yes if height requirements are met but if not definitely 10-11
Yes
Its their height that is measured. Not 100% on the number of inches but the website may say
I'm not sure on 9 but I know 10 can drive the family sized carts. You should be able to find it on their website and 9 should be fine!
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