python3, 113 bytes

Result

AC

Duration

608ms

Code [DL]

c=list(input())
for i in range(len(c)):
	if ord(c[i+1])<58:print(c[i]*int(c[i+1]))
	elif 58<ord(c[i]):print(c[i])

stdin

i4y9n3d7n8a6b7a4d4oj2i3g7k9k9x6v6f6e6v3q4m3q9y6cy6lhwr5h3c9s6p4v6u6l2o2t2s5z5w4j8gg7ob4n9o3q3

stdout

iiii
yyyyyyyyy
nnn
ddddddd
nnnnnnnn
aaaaaa
bbbbbbb
aaaa
dddd
o
jj
iii
ggggggg
kkkkkkkkk
kkkkkkkkk
xxxxxx
vvvvvv
ffffff
eeeeee
vvv
qqqq
mmm
qqqqqqqqq
yyyyyy
c
yyyyyy
l
h
w
rrrrr
hhh
ccccccccc
ssssss
pppp
vvvvvv
uuuuuu
ll
oo
tt
sssss
zzzzz
wwww
jjjjjjjj
g
ggggggg
o
bbbb
nnnnnnnnn
ooo
qqq

stderr

Traceback (most recent call last):
  File "/volume/CODE", line 3, in <module>
    if ord(c[i+1])<58:print(c[i]*int(c[i+1]))
IndexError: list index out of range

strace