I've finally got some time off to give New Vegas a serious play through, I know in the first game a character with a INT of 9 was the way to go, but I've heard this is not as effective this time around. Is it still worth going for a high INT build?

Yeah, Each INT Point is 0.5 Skill points. So 10 INT gives you 15 Skill points when you level up.

Take the Educated! perk ASAP

I think the consensus is 'fine if you want every possible skill point, but not necessary to do well'. The impact of INT on skills is less, you only get half a skill point per, probably so you don't feel like you're missing out and can put SPECIAL points on stats that suit other playstyles.

* You get 0.5 skill point per level for each INT point. But if your INT isn't even, you don't lose half points, you will be getting an extra point every two levels.
* You get a bonus to Medicine, Repair and Science, +2 points for each INT level. All three useful skills you want to level up eventually.
* You also get some "smart-ass" dialogues rarely to underline your elitism if you're high on INT

I consider this the mommy of all other attributes andI hate having less than 8 points in it. Preferably 9 (remove 4 from CHA and add to INT basically) and then implant on top of it to get to 10.

So is INT still an almost 'required' stat to have around 8-9 at the start like it was in 3?

Highest Intelligence Check I have seen is only 8. I may have seen a 9 somewhere, but I don't remember ever seeing a 10.

So highest Int you would need is only a 8. But you should get Endurance 9 if you want all the implants.

Is it worth using the Intensive Training perk to put points into SPECIAL stats or just rely on implants for stat boosting?

I would say for your very first perk Intensive Training isn't such a bad idea to boost whatever you feel you are lacking in.

My high Int Character is doing fine still crits so much lol

Intelligence below 6 opens up the "slow" or "stupid" dialogue options (they're rare, but pretty funny). Intelligence at 7 or 8 opens up the "elitist" or "arrogant" dialogue options, which are also funny.

If you're looking to maximize skill points, start with 9, get an implant for it as soon as possible, and take the comprehension and educated perks. Every skill has at least 4 books, with most having 5, Guns having 6 and Sneak 7. This means that if you scavenge for everything, you're looking at around 70 points from Comprehension, and 52 from Educated.

However, Luck is also another good stat to have at 7+ (funny dialogue, and overall the best combat stat outside of endurance [for implants] and agility [for AP]), and the only kind of weapons you can basically utilize fully starting with 4 strength are energy (Guns needs 5 + implant + a perk to efficiently use the AMR and miniguns). So no, Intelligence isn't all that important. Strength, Luck and perk requirements for other stats (6 END, 6 AGI, etc.) are what you should be looking at if you want the most out of a combat oriented character, with extra consideration for Endurance to take advantage of implants.

I suppose my main goal is a combat effective character, so Agility, Luck, Endurance, but doesn't Perception affect gun skills now? Seems all the stats are very useful, hard to pick between them.