Ah... hooking IEMs up. There's the rub. As a sound reinforcement professional, I always blanche a little when I see fellow TB-ers cavalierly recommend IEMs as THE solution to all sorts of issues, including whether or not a beginning bass player should even buy an amp. IEMs ARE the solution to all sorts of monitoring problems, including ones like yours, but using them injects complications that not everyone wants, or is even equipped to deal with.
A comprehensive discussion of IEMs is beyond the scope of this thread, but basically, you have to have your own separate monitor 'mix' to send to the IEMs. Ideally, this would come from the console providing the monitor sends, whether that's an on-stage monitor console or the FOH board. Modern digital desks at all levels have gobs of output busses, so this is a lot more likely to be a viable option than it was in the old analog days, when a request for "an extra mix from the monitor console" was likely to be met with a gruff, curt, or sarcastic response. Still, if you're working down in the trenches, where monitor situations are highly variable, you need to come equipped to provide your own little monitor system if necessary. It could be as basic as little 4-channel mixer that allows you to mix your bass signal with a line-level send from some other source, like an existing monitor mix. If you are likely to encounter situations where there is no monitor system at all, worst case, you can throw up a mic or two of your own to plug into your mixer. Also, a couple of XLR 'wye' cables would allow you to 'split' the mic signal from a couple of select sources -- like the kick drum mic -- but as you can see, it quickly starts to add up to a level of hassle not everyone wants to deal with. This is the source of my skepticism of IEMs being THE solution for good audio. And I REALLY don't want to weigh in on the possibility of 'going ampless' in your situation, except to say that means you'll always be dependent on the quality of the house PA system for your sound -- I'd say with fully half of the club PA's I encounter, the low-end performance isn't up to the task.