if proper quarantine protocol is taken, then your ball python should be fine, if your boa happens to have ibd. there still isnt a whole lot known about ibd at this time. last research and articles ive read, showed that they are going up the route that a specific snake mite may be the culprit. but who know, the bad part of ibd in boas, is they can be a host for it for years and years. pythons tend to show signs and die much sooner. so all you can do is qurantine for a few months, if no sign then resume as normal. still always practice as aseptic techniques as possible, handle other snakes first then boas, wash and disinfect your hands and any other parts of the body the boa has touched, etc.