I think it depends on how big and high. However you would be unwise to go for less than 15cm of top soil and 30cm of subsoil and ideally 25cm of top soil.
I would question brick rubble - if there are too many air spaces within it roots might not be able to explore for moisture. By definition heaped earth is free draining and drought will be a major constraint.
Vegetation is not that good at attenuating noise so the higher the bank to reflect noise the better. I notice ones around local housing estates are at least 2m high and 5m wide - but few private homeowners will be able to spare that much land.
It is noticeable how much noise increases after leaf fall on hedges adjoining roads so I suggest adding plenty of evergreens.
It is usual to use a fabric to retain the soil - either woven polypropylene or natural biodegradeable material. These will suppress weeds that can quickly stunt new plantings of woody plants.
It is also usual to plant numerous small, inexpensive, trees and shrubs called whips to get good groundcover quickly which will stablise soil. Later management might involve thinning out and coppicing to get the height and density you desire.
Naturally careful watering for at least two years after planting, is needed if plants are to get established.
Finally builders are seldom fit to be trusted in matters gardening and if significant expense is involved I suggest getting a horticultural professional to at least check the scheme on site - ones affilliated to BALI or APL are likely to be competant.
Beware the bat-eared bogweevil