I would agree with the hand plane suggestion, but glue can be hard on an iron. If it's just one side and the other is already flat, go for it but I'd take the rough stuff off with a cheaper cutter sharpened with a good curve - almost like a scrub, then finish up with a good smoother. The router on rails method is very easy if the sides are straight, but if you've already cut it into a circle then it's not so easy. And if both sides need work then you could be ending up with a tabletop that is too thin.
If you know anyone with an openend sander like a performax 16/32 that would make it go faster but you still risk an undersized top.
And is the raised area where the glue swelled the grain, or is the entire thing from board to board wavy because it wasn't clamped up evenly? Sometimes it's easier if you've got enough wiggle room to take it over to the TS, rip apart all those joints, clean up the edges, and try again.
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