Am getting back into IDPA plus USPSA. Want a holster that will do both.
The SafariLand Holster selector indicates that the "578 - GLS™ PRO-FIT™ HOLSTER" fits the TP9SF.
Found one on-line for $34.99 shipped but the pix of the fit list does not have Canik listed but does have the G17.
Is this the correct holster?

yes

I ran one with mine.  I run 578GLS long

Basically the holsters fit fat Glock-like trigger guard or skinny 1911-like trigger guard.  You should be fine with the G17 version.  The other size factor is the barrel length.  I have one of each for various pistols, usually require little adjustment after the first time.

I attached a QLS attachment to the holster and can snap it in and out of a range belt with drop or have a belt mount for IDPA.  They are decent holsters and should not slow you down.