"From a legal standpoint - suspending someone isn't exactly an option."
The National Rugby League has a so-called "no-blame" policy. It requires players charged with a serious criminal offence to be stood down (not play) until such time as the charge has been through the courts and the player either has been acquitted or has served his sentence (if found guilty). That policy was tested in the Federal Court and was upheld (https://www.zerotackle.com/breaking-de-belin-federal-court-ruling-handed-down-44150/).
So, from a legal standpoint, it's possible to establish contracts that permit someone to be suspended in a circumstance such as Creek's. The NBL would just need to have adopted a rule or policy such as the NRL's, or SEM Phoenix have included a suitable clause in player contracts.
The NRL adopted its policy 2 years ago (March 2019). Overseas professional sporting leagues/teams have had even stricter policies in relation to domestic violence for a lot longer (e.g., Kareem Hunt and Ezekiel Elliott cases in the USA's NFL). With such high profile precedents, either NBL decided it wasn't necessary/appropriate, or they weren't paying attention. My tip is the latter - that's more consistent with the league's reactive approach to policies and rule making over the past 5 years.