No insecticide sprays, organic or otherwise, are recommended for Spotted Lanternfly (SLF), for several reasons. They don't cause serious plant damage (except potentially in vineyards, which of course does not apply here), and should not reduce the plant's yield. As you noticed with hand squishing or trying to capture them, they are very jumpy and shy, so will also avoid most contact with a spray, and the types of sprays that are the lowest-toxicity for minimal risk of harm need to contact the pest thoroughly in order to work well. (Their dried residues will not have any effect.) Additionally, no spray will target only SLF; they all have the potential to harm beneficial insects or other organisms if they come into contact with them, especially any kinds of sprays that do have a residual effect (dried-on spray that will kill insects touching it later).

Do not use rubbing alcohol, as it is not a pesticide. Alcohol can also remove the natural, protective wax layer from plant leaves, causing "burn" damage that will be worse than the insect issue itself. (Boxwoods also have a heavy waxy layer on their leaves.) Even if not burned by desiccation damage, the compromised leaves could be more vulnerable to infections. Unless populations are very high, boxwood psyllids are nestled in the leaves that cup around their feeding site, so are unlikely to be much impacted by any contact-type insecticide. Plus, blasting them with a strong spray of plain hose water is usually enough by itself to suppress a psyllid outbreak.

If you try using an insecticide on the SLF, go with either horticultural oil (neem being one type in this category) or insecticidal soap. Follow all product label directions (make sure it's labeled for use on vegetables, for example), and re-treatment will be needed fairly often in order to maintain suppression of the lanternflies. The label should state when to stop using the product before harvest, though often with these low-toxicity ingredients it's only a day or so at the most.

Miri