Trolling plates suck unless there is no wind or waves whatsoever because they make the boat really hard to handle. I hated mine. Buckets work fine but bounce off the boat in the waves and drive me nuts (whatever you drag needs to be off the forward cleats, next to the bow so you aren't dragging buckets in the fish fighting area). Trolling bags aka drift socks aka sea anchors are the ticket. They actually greatly enhance how your boat handles and keep it stable in the wind. You tie them off the forward cleat, rear of the bag on the stern cleat and you can dump them from the back of the boat. The best I have seen are by Amish Outfitters and they have a two pack deal. https://www.amishoutfitters.com/
i would have a prop shop tune the prop to go slower, just remember not to over rev on the upper end. on my 115 ive always had different pitched props depending what i wanted to do. you can also play with the tilt settings on the motor
looks like the 9.9 has multiple pitch sizes, i would not have thought that on that size motorhttps://www.rubexprops.com/boat-propellers/Honda/?motor=K0099A&ver=a&model=9.9HP%20BF9.9%20(8%20Spline)
alot fish bait at .6 to 1.1 mph. maine lakes its all year, nh mostly at iceout, that and some are fishing mostly for lake trout which is better at slow speeds most of the year