There unfortunately is no chord inversion or substitution that will quite get you to a madd9 chord in BIAB. Closest I can think of would be using a 7susb13 chord with an altered root - so if you were looking for an Amadd9 then you could use an E7susb13/A. However that would give you an unwanted "D" (the 7th) in addition to the ACEB that you need. An Esus with an added b13 would give you the right notes (if played with an A in the bass) but unfortunately that's not an option. An Esus/C would give you the right notes, but the wrong root.

It's a pity because the madd9 chord is not uncommon in certain genres - for example, some movie composers are very fond of it.

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