I always assume if a blank is covered in wax then it is probably wet (green). Keep in mind that wood will dry faster from endgrain, and also it will shrink across the grain more than with the grain (this is why tables will have loose tenon breadboard ends - the wood will move a lot along the width, but not as much on the length). It is this movement that causes the crack - the wood is shrinking as it dries but has nowhere to go because of the brass tube. If you remove the wax leave the wax on the ends as this will help prevent cracking/checking. Pen blanks will dry fairly quick - a couple weeks to a month or so. Weigh them with a kitchen scale and write the weight on them, check weekly and when the weight stop dropping they are dry. I would expect to lose about 10-15% of the weight of a waxed blank from a major outlet that has a lot of turnover. But this depends on a lot of factors. The "1 year per inch of thickness" rule of thumb that you'll find for air drying lumber doesn't really apply to pen blank sizes. You can speed up drying by using a dehumidifier, toaster oven, microwave, boiling in water, placing in a warm spot like the dash of your car, or a place with good air flow like a HVAC return.
Bloodwood isn't particularly prone to cracking. Use some care to not generate too much heat while drilling. I like to use gorilla glue (foaming urethane type) for gluing tubes - I feel that this allows for some movement of the wood material relative to the brass.