Q 19 can a artificer with a caster level from another source, say 17 levels of wizard, use a Use Magic Device check to create a scroll of a 9th level cleric spell? (Just as a example) The wording on the artificer’s item creation feature makes me think the feature that gives them a CL and the ability to emulate a item for crafting are different mechanically but i’m not sure.

Q 19 b How does this interact with a psionic artificer and Psion for example?

Q 20 Would a wizard or other caster that prepares from a book that has a spell too high for them to cast scribed in said book count as knowing the spell? Assuming it’s a spell they could theoretically cast at a appropriate level anyway.