Amate is the best choice among Schefflera species. Yours appears to be healthy and the centipedes you are finding are not doing any harm to the plant. Their presence simply means that the nursery grower did not use a sterile potting soil.
One choice is to ignore them (assuming they don't gross you out!) and they may eventually die off.
Otherwise, you might try setting the pot in a tub filled with water for several hours. The flooding of the soil may drive them out in search of air.
There are systemic pesticides that can be added to the soil, but I don't particularly recommend them because they are toxic.
