Roots follow moisture, it’s not unusual to see roots coming out the bottom of pots. They will air-prune meaning the bits exposed to the air will naturally die back. Nothing to concern about, nothing necessary to do.
Roots grow out to the sides and down. One of the first places they end up is the drain holes so it does not mean the tree is root bound or needs something. It is quite normal for roots to come out the bottom of the pot.
Normally this would be the case but BC are often kept in water trays so the roots don't get exposed to air and will continue to grow. I have just cut the roots off some melaleucas that lived in a water tray all summer and most of the winter here - just masses of fine feeder roots taking advantage of the abundant water. Roots out the bottom is not usually a problem until the roots get thick enough to seal off the drain holes or if one root beats all the others and gets unduly thick which can ruin otherwise good nebari.
As long as those roots don't get out of hand you can leave them. The tree will grow stronger for it but if you feel like cutting them off that won't do any harm to the tree.