Building up a 1988 Schwinn Circuit frame with new parts I’m very new to vintage road bikes, I’ve had an 1988 Schwinn Circuit frame laying around for years. Is it possible to build it up using newer components?

I understand that it originally came with an 7 speed Sante’ group. I’d like to build it with an 9 or 10 speed group if possible. I’ve heard that you may have to widen the rear to 130mm?
It's certainly possible to build late 80s frames up with modern components. The two biggest issues you may run into are the rear dropout spacing and wheel size. 

Older bikes with fewer rear gears had narrower rear dropout spacing than modern ones designed for 10 and 11 speed drive trains. A frame designed for a 7 speed drivetrain very likely has a 126mm rear. These can easily be widened to 130mm. Detailed instructions can easily be found RJ the Bike Guy has a good instruction video on his YouTube Channel.

Older road bikes were designed around '27 inch' wheels with 630mm diameter rims. Modern bikes are designed around '700c' wheels with 622 diameter rims. I'm not sure what wheel size 80s bikes used. Tf your frame is designed for 27" wheels, new wheels and tires are available, but if you want to switch to 700c for a vastly wider array of choices you have to fit long reach brake calipers as obviously the brake mounting holes are 4mm further from the axle axis.