Current Transformer flux and back emf with only one turn
You are confusing terms.
When you talk about/model an inductor with inductance \$L\$ $$ v(t) =L \frac{\mathrm{d}i(t)} {\mathrm{d}t}$$
When you talk about/model a transformer $$\sum_k N_kI_k=Hl$$ for the \$k\$ windings on a transformer.
In this case the ampere-tuns balance in a transformer equivalent circuit $$Hl =\frac{Bl}{\mu}\propto I_0 \approx 0$$ can also be seen as the current through the magnetising -impedance or -branch of the transformer. Here Wikipedia correctly says for a two-winding transformer model:

With sinusoidal supply, core flux (and the current) lags the induced EMF by 90°.

However, this is only valid for \$I_M\$ and not for \$I_C\$ in the equivalent circuit below.

The circuit is valid for both VTs and each CT core.