No logic in standing
"Soft 18 vs dealer 9 and 10 is not in I18 list."
It wouldn't be on an I118 list, either!! :-)
"If there are an index numbers to indicate Stand, they must be really very, very high or there might be no index numbers at all."
None at all. It makes no sense to stand. There's no logic to it. This isn't a case of avoiding busting and hoping for a low card for the dealer in the hole. You have a hand that can't break by hitting. With extremely high counts, you mmay very well get a 10, but if you're using an ace-reckoned count, you might also get an ace, and there's always a chance of catching a 2 or 3. The dealer, of course, will also have a good shot at a 10 in the hole, to beat your 18 with his 19 or 20, if you stand, so there simply is no logic -- or any count -- for which standing would make any sense.
"So I think Hit is always the way to go. How many cards to reach soft 18 doesn't matter."
Right.
"Interested to know if anybody can get the index numbers for these situations."
See above. There shouldn't be any index for them.
Don