Smuggling 102 Hints :
Heat outside ~5.5km from the front Station entrance is irrelevant. No Security NPC will ever venture that far, unless in the rare occasion you disengaged into an already alive instance and Security had business in the vicinity.
The moment when you passed the critical area, you'll notice your heat was already all the way back up to normal - just when you needed to be cold the most. 3km and closer is where it gets critical.
IF they have business, i.e. they're engaging another Target that scanned as Wanted - all Security Ships will join that fight. During that period, you technically could run in with Docking Computer and 90% heat and noone will be left to scan you
Keeping Throttle up somewhat sabotages your Silent Running - Thrusters at full aren't covered by it and can give you away (Engine Exhaust = external, thus Silent Running can't cover them).
Keeping the Vector with FA off and at speed - but Throttles in idle - reduces your signature. Additionally prevents building up excess and undesired heat from the Engines @ full Throttle.
The worst danger in a Type-9 is encountering opposite Traffic while already close to the entrance. Then you're screwed *g*
Using above details, you'll be able to run in shielded (if you wish, an unshielded Type-9 carrying lots of expensive stuff attracts alot of NPC Pirates) and technically won't need Silent Running.
Latter has been proven to be rather ineffective at preventing Security Scans all by itself - only the % heat and your graphical thermal signature is what matters when it comes to Security Scans.
Just stay cold inside 5km and you'll be fine. A 2nd or 3rd Heat sink launcher on another Firing Group doesn't cost much, so you'll be able to carry as many as you need and spam them at all times
-- edit --
Just parked my own Type-9 (fully kitted, 28% heat @ idle) 5km in front of a large Orbis Station.
No Security Ships came closer than 3.9km doing their standard Orbits.
Upon closing in, I saw one Security NPC approaching me - so I went Silent running when it was still 1.7km out.
As expected, the Scan was conducted from 1km range without problems by the NPC - as I had approx. 38% heat at that time (no heat sinks).