Chrisf8626 wrote: I am a beginner.
"Beginners" (even FIT beginners) shouldn't be on a 7'4" hard board. Your 9'0" soft has overly thick boxy full rails that gives you a false sense of stability and float. Even going down to a 8'2" hard board would've been difficult enough. You are not ready for that 7'4".
Chrisf8626 wrote: I am struggling to get up on the mini mal and I think it might be something to do with my position on the board. I’m 5 foot 8, 65kgs and fairly fit so I wouldn’t think popping up should be too much of a problem.
So for any problem, I always recommend to look back two steps. So you're sinking, so a step back is your Pop Up ( which you think shouldn't be too much of a problem ) and two steps back is your Paddle.
So since your fit and thus have a strong paddle, then how is your Pop Up ? Are you getting to your feet in one smooth action or crawling up onto one knee then getting up to both feet ( which a lot of beginners tend to do ) ? If the latter, that millisecond delay is enough to loose the wave and momentum to keep the board up on the surface of the water.
Also are you looking down at your feet ? Looking down at the deck to check your feet positioning or see if the nose is going under actually brings the nose UP and stalls out the board.