No way to tell without trying it. Wouldn't even say for sure it would help at all. Springers are well known for NOT shooting well benched, but yours sounds weird. My R9 .177 GF shot okay benched when stock, but was really buzzy. I dropped a JM kit in it yesterday (I'd already deburred, lubed, and replaced the piston seal), and was shooting 1/2" groups at 35 yards with FTT's. That was holding the rifle to my shoulder, and the forearm on a rest. A fairly firm hold was actually giving me the best results. Nice dead blow shot cycle, and no more buzz.
Two suggestions, make sure the forearm can slip on the front rest, and lose the rear rest, try holding it yourself. If all you ever intend to do is shoot bench rest, then your current technique is fine. But if not, you need to come up with a technique that you can replicate in the field. I shoot the way I do from a bench, because I can shoot in a similar fashion off the bench, either by using an improvised front rest, or even kneeling and supporting my left arm on my knee. Groups will open up, of course, but it's still plenty accurate enough for hunting.
BTW, I passed on buying an R9 several years back because of their reputation for being hold sensitive. Based on my rifle, I'd have to say that reputation is over blown. I recently went back to springers after shooting nothing but PCP's for almost 3 years, and I've had no problems that I'd characterize as hold sensitivity. Now, all 4 of the rifles I have are tuned by me, two with Vortek kits, and two with JM parts. All of which is my long winded way of saying you can't go wrong getting your R9 tuned. Good luck.
Dave