Final decision
 

Thank you to all those who have helped me and commented on my previous posts.

Narrowed it down to the Boardman ADV 8.9 and Boardman ADV 9.0. Unfortunately I don't know enough about bikes to know if the 9.0 is a significant upgrade and worth the extra cost? Thank you for your thoughts and opinions.

https://99spokes.com/en-GB/compare?bikes=boardman-adv-8.9-2021,boardman-adv-9.0-2021

The 9.0 is a carbon frame and 11sp drivetrain.
The 8.9 is an aluminum frame and 10sp drivetrain.
The 8.9 has a lower number carbon fork, so maybe it's heavier?...who knows.
The 8.9 uses an fsa crank and the 9.0 has a shimano.

Are those differences worth $1000? Who knows. There is no actual firm yes or no to such a question.
As a beginner, both bikes are well beyond your ability. You won't max out on either. If you aren't sure whether you even like cycling, bit the cheaper one since it's still more bike than you need.

The ADV 8.9 is only 0.1 lower but $1000 less expensive?

The choice is absolutely transparent.

The difference between 8.9 and 9.0 is meaningless…it’s just how Boardman names the bikes.

That said, the advice of mstateglfr is solid.

if OP wants to ride British bridleway with rust jammed farm/field gates, he might need to consider carrying the bike over the gate... When looking, I was considering classic Aluminium frame 1x11 or 2x9 and bit the bullet and went for carbon because of these gates...

Boardman are good bike (mate of mine loves his 8.9E) but since OP is in the UK and before heading to Halfords, planet X freeranger might be an option too.

An aluminum frame bike with carbon fork will be 1.5# heavier than a carbon frame bike with carbon fork and identical components.
If that 1.5# is the difference between being able to pick the bike up and having to turn around at a gate, then yeah thats a critical weight difference. Based on typical spec, there is a decent chance a 2x9 drivetrain and components offsets a good bit of that frame weight savings when compared to a 1x11 drivetrain and components.

I’d definitely spend the extra £600 for the CF 9.0, because if upgrading is a thing, as the OP indicates, yeah, getting a CF frame for that money is something you’re only going to do when purchasing new. It’ll cost a whole lot more if they were to buy the 8.9 alu and try to replace the frame with CF later.

So yeah, if the money is there to do it without having to sacrifice too much elsewhere, I say get the 9.0. It’s got slightly sportier geometry, is kitted out with mounts, looks great, and you chop 2.8lbs (according to Boardman specs) of weight right off the top. That’s not to say I or anyone else couldn’t have fun on the 8.9, only that those kinds of upgrades are worth money and cost money, and so if you’ve got it, you might as well spend it.

That s why i pointed out the planet x free ranger with rival 1x11 in 700 or 650.
there is room for a few improvement if needed.

I find in general, carbon rides noticeably better than Aluminum on gravel, but that really depends on how the bike is designed and manufactured. Never ridden a boardman, so not sure how this applies here. I did think it was interesting that Salsa stated that their tests showed their Aluminum bike was more compliant than the previous generation TI bike - but Salsa uses formed Aluminum, not just the stock round stuff.