Scan 1
Nine Height = 1.89 m (543 px)
Shield Height = 3.21961325967 m (925 px)
Nine's Shield here looks like a perfect circle, so this should be fine.
Scan 2
This is what's hitting his shield the frame after, so it should be safe to assume this is at least the same size as his shield, since it's not visible in the shot.
Shield Height = 3.21961325967 (118 px)
Crater Size = 23.9288205825 m (877 px)
Scan 3
The picture here is meant to been seen from bottom to top, not top to bottom.
Crater Size = 23.9288205825 m (387 px)
Explosion Diameter = 93.180187643 m (1507 px)
Explosion Radius = 46.5900938215 m
W = R^3*((27136*P+8649)^(1/2)/13568-93/13568)^2
W is yield in tons of tnt, R is radius in meters, and P is pressure of the shockwave in bars, the standard overpressure is 20 psi or 1.37895 bars.
46.5900938215^3*((27136*1.37895+8649)^(1/2)/13568-93/13568)^2 = 8.12 Tons of TNT (Large Building level+)