I would do the poles first. I have had to use poles before to slow down my horse when he just got way too hyped up for his own good and basically refused to trot (I gently squeezed with both legs etc and he would not do anything but canter no matter what I did). So we placed ground rails down in front to make him slow down and behave to the jump. He never had issues with running out after a jump so we just spaced the rails prior to the jump. He was forced to trot his started cross rail instead of barreling through everything. Olympics also help (personally I hate them...). We basically set up our poles leading to an olympic so he had to obey to and between jumps.

I would also suggest maybe doing a bit more of a work out prior to jumping. My horse gets extremely strong and powerful over the jumps when he has not had enough excercise and will settle partially into the jumping when he has worn down a bit. So sometimes just a long and more intense warm up can really make the difference in how they behave.

Figure 8's can also be good I would just use these as a last resort for you. Since you horse seems to not have issues with refusals I dont think this would cause issues, as long as you dont try to start your circle only a stride or two off from the jump. I would just do this as soon as they start getting strong. Just break to a trot and trot a circle then move back to the calm lope then back to the fence (starting back at the start, not where the horse got strong) and go again.

The only thing I wouldnt do would be to halt the horse directly in front of the jump or to start the circle directly in front of the jump. Lots of horses are trained to not even think about refusal/stopping so you dont want to get the idea in their head that "Wait you mean I CAN stop in front of a jump?". So just be careful how close you do these manuevers to the jump