If you can buy a 9mm Tactical buy it because HK never made one, at least not for any sales market (there may have been a prototype true Tac 9mm but I doubt it). The 9SD is no more a Tactical than my butt is. The 9SD has the adjustable sights and threaded barrel, but regardless of what it says on web sites, it does not have any match trigger parts nor is the barrel o-ringed. It is not a Tactical unless it has all those items, plus, it does not say Tactical on the slide.
So, that narrows the field down some.
Caliber, no brainer there, .45 ACP. There is a surprise.
Handgun, Compact if there is any CCW use in your future.
If for HD and range shits and giggles, the Tactical is the only choice IMO. While the TB on the Tac may make it undesirable as a CCW I do not think anyone would give you any grief if it were used for home defense. Once a perp is inside your home most localities pretty much give you free rein.