My sb 9 had a similar sqeek that drove me nuts! Turned to be in the cone pulley screw was too tight! After cleaning, I filled this area with teflon grease and lightly tightening screw, my problem solved!
On a different machine it squeaked and spindle split bearings would get hot and stop turning! They would lose all oil, I put o/w/5 synthetic oil in bearings and haven't had it stop anymore! Put teflon grease in cone head also. As for sqeek it was the zipper clip on belt every time it went around, learned to live it . This machine sit along time without use and spins easily still with syn oil. My 2 cents.