Can Investing 8-9% interest rate loan into index funds be a calculated risk ?

From what little investing knowledge i have , it is commonly considered that index funds over 5-10years safely give 10-11% CAGR , lets consider a hypothetical , a person has a upcoming student loan of 40L , he already has more than that saved up and a decent income too. he dosent need a loan but he takes a calculated risk and manages to get 40L education loan over 5 years at 9% lets say , to be clear he has enough income to easily pay the EMI too in any case. He puts the 40L straight into index fund , be it altogether or yearly (depending on how bank releases money) while continuing to pay the EMI out of his own pocket , Lets consider the worst case : The next 5 years his mutual fund does bad and is not eveing giving 9% CAGR , he dosent sell , he holds onto the investment and keeps paying emi out of own pocket because he can , lets say worst case it takes another 4-5 years for markets to get back on track and from what i know even if there are lot of downs( covid , 2009 , dotcom bubble etc ... ) , the market normalizes over time and nets 10-12% CAGR , and the guy exits his investment at 10-12% CAGR in the next 4-5 years whenever the market does well . Even in the worst case if the person has patience and enough savings/salary to pay off EMI's he got net 2-3% CAGR positive on his 40L that he invested , his education was paid by the bank ? Yes i know the markets will go down , but if one has patience to wait out till the markets normalize in the next 4-5 years even after the loan tenure is over ,and you get 10-11% CAGR on your initial investment , ain't it a calculated risk ? I feel as long as one has ability to pay the EMI's and enough savings to mitigate the risk , the person can get the bank to fund his education... Idk i might be completely wrong or missing something , enlighten me.